So what is the bottom line, is there or is there not a difference?

How about current models?

Well, this thread had a rocky start, but ended up being very educational.

One thing though: I haven't heard of anybody poking a hole in a BM flattop upper with a pencil. How did they and others 'fix' this issue without following Colt's lead?

Quoted: Quoted: last time i looked at this thread, it was 2 pages.  I'm not going to go back and read through arguing.  So, I'll just ask, did anyone suggest that maybe Colt tried to throw other companies off by making a few minor changes when they introduced the flattop M4? Again, according to a link posted earlier, the initial flattop models had *very* thin material at the top under the rails (apparently enough to push a pencil through? would like to know more about this story).  Colt thickened the area which raised the rails. They chose to raise the front sight so existing rear iron sights would still zero.  Their plan worked perfectly until all the meddling kids came around and decided not to use the "F" FSB on flattops... And of course, I may be wrong, but that's how I understand it.

So then, when Colt eventually started to use the now Mil-spec shorter flattop upper receivers they had to make up for the loss of the taller flat top by making the DCH sights taller so that they would work with the taller F FSBs? This sounds right to me, can anyone else confirm if this is right?

Quoted: Quoted: Quoted: last time i looked at this thread, it was 2 pages.  I'm not going to go back and read through arguing.  So, I'll just ask, did anyone suggest that maybe Colt tried to throw other companies off by making a few minor changes when they introduced the flattop M4? Again, according to a link posted earlier, the initial flattop models had *very* thin material at the top under the rails (apparently enough to push a pencil through? would like to know more about this story).  Colt thickened the area which raised the rails. They chose to raise the front sight so existing rear iron sights would still zero.  Their plan worked perfectly until all the meddling kids came around and decided not to use the "F" FSB on flattops... And of course, I may be wrong, but that's how I understand it. So then, when Colt eventually started to use the now Mil-spec shorter flattop upper receivers they had to make up for the loss of the taller flat top by making the DCH sights taller so that they would work with the taller F FSBs? This sounds right to me, can anyone else confirm if this is right?

I believe SNorman is speculating that Military/COLT changed the design of the original flattop to a flattop that has more meat in the rail area (made it thicker at the top)... A thicker top would cause the DCH to set higher... To compensate for the height difference, COLT then changed the design of the FSB to what is now known as the "F" marked base...  

The way I understand it, the milspec DCH never changed, it was the milspec FSB that was redesigned (FSP area milled to be taller)...

Heres my thoughts...

The pencil test was done during the trial period before the actual flattop was produced for use by the military... The pencil theory played a part in the development and  re-engineering of the original and only MIL-STD-1913 flattop upper receiver...

The Flattop, Detachable Carry Handle and "F" marked Front Sight Base is the original design of the M4A1 carbine...  

 The .030" and .040" taller Front Sight Posts are a "fix", but it could end up being exposed by it protruding past the protective ears on the FSB, allowing it to be vulnerable to snagging and/or being bent, so the reliable sensible "fix" is, and to avoid having to replace the FSB, to use a shorter DCH...  

The .030" and .040" taller Front Sight Posts are a "fix", but it could end up being exposed by it protruding past the protective ears on the FSB, allowing it to be vulnerable to snagging and/or being bent,

The "F" FSB raises the top of the post too, so it's also not as protected as the original A2 post.  (It should be a little harder to bend because it's shorter, but it's not more protected.)

Quoted: The .030" and .040" taller Front Sight Posts are a "fix", but it could end up being exposed by it protruding past the protective ears on the FSB, allowing it to be vulnerable to snagging and/or being bent,   The "F" FSB raises the top of the post too, so it's also not as protected as the original A2 post.  (It should be a little harder to bend because it's shorter, but it's not more protected.)

All of the posts on my "F" marked FSB's are well protected by the ears...

All of the posts on my "F" marked FSB's are well protected by the ears...

Then a non-"F" with .040" taller post would be just as protected.  An A2 with regular height post would be even more protected.

So, if the .040" was NOT added to the upper for structural integrity, but rather only to the DCH, the question remains; why? And, if the answer to that question is: "Because the FSB utilizes a .040" higher FSP mount," then the next logical question is; why?

Don't flame me if these questions have been satisfactorily answered. I have read all the posts but still am unclear on this issue of 'why'. I mean aren't the A2's sights already higher than ideal off of the bore axis? What advantage was there in Colt effectively changing the entire sight height? Even if you make the argument that noone should ever have produced shorter DCH's, there still would be 2 different FSB configurations.

That is the $64,000 question isn't it?  I can't think of any good reason for Colt to make the flattop sights .040" higher than the non-flattop sights.  Which is probably why everybody else like BM just uses the the same FSB on both.  But since it's Colt I guess we shouldn't be surprised.  Not after the big pivot pins, the sear blocks, the "C" bolt carriers, and the large trigger & hammer pins.  

Colt has done a lot of things to be "different" but this just isn't tripping my different-meter right now.

I think they had a legitimate reason for doing this.

WIZZO

Quoted: So, if the .040" was NOT added to the upper for structural integrity, but rather only to the DCH, the question remains; why? And, if the answer to that question is: "Because the FSB utilizes a .040" higher FSP mount," then the next logical question is; why? Don't flame me if these questions have been satisfactorily answered. I have read all the posts but still am unclear on this issue of 'why'. I mean aren't the A2's sights already higher than ideal off of the bore axis? What advantage was there in Colt effectively changing the entire sight height? Even if you make the argument that noone should ever have produced shorter DCH's, there still would be 2 different FSB configurations.

OK here is the deal... the .040" was NOT added to the DCH.  .040" was removed from the DCH by non-standard makers who wanted to use the non-"F" marked FSB.

Your other questions have already been answered.

Quoted: That is the $64,000 question isn't it?  I can't think of any good reason for Colt to make the flattop sights .040" higher than the non-flattop sights.  Which is probably why everybody else like BM just uses the the same FSB on both.  But since it's Colt I guess we shouldn't be surprised.  Not after the big pivot pins, the sear blocks, the "C" bolt carriers, and the large trigger & hammer pins.

Try reading the whole thread.

Quoted: OK here is the deal... the .040" was NOT added to the DCH.  .040" was removed from the DCH by non-standard makers who wanted to use the non-"F" marked FSB.

+1

Non-Colt DCHs are .040" lower than Colt DCHs to work with the normal (non-"F") FSBs.  But why did Colt make the "F" height FSBs in the first place?  If they really did change the height of the flattop uppers by .040" at some point then why didn't they just adjust the height of the DCH at the same time?  Raising the FSB to allow the use of the old DCHs on the new uppers seems to me like far more trouble than just fixing the DCH.  Were there really that many DCHs out there to worry about?  Especially since the reason you got a flat-top was so you could mount optics in place of the handle?  

It was probably easier (read cheaper) to do the minor re-design of the FSB compared to doing a little re-designing of the DCH.

WIZZO

Heres a bit of info I put together last night... It refers to, some of the changes (upgrades) the military had made to the A1, and with the design of the new M4A1... I have more (2000 - present) to read later tonight and after sorting through it I will add to this information...


1978...
The US Army and USMC begin discussions with Colt concerning the development of a product-improved M16A1 to replace their stores of severely worn rifles.

**************************************************************
September 1979:
USMC brass hold a strategy meeting to examine ways to improve their small arms inventory. Four mutually exclusive options are considered: 1) Retain the M16A1 rifle as is; 2) Reintroduce the M14; 3) Review other potential replacements; and 4) Upgrade the M16A1.

*****************************************************
1980:
January: The USMC opens unilateral negotiations with Colt to supply three product-improved M16A1 rifles.

February: A JSSAP meeting is held. It is determined that there is enough interest to justify a Joint Service Rifle Product Improvement Program.

April: The House Armed Services Committee requests that JSSAP conduct a study of the M16A1 rifle with an eye to possible improvements and eventual replacement.

April: The US Army Infantry School (USAIS) sends a letter to JSSAP outlining their recommendations for a product-improved M16A1. The USAIS desires a heavier barrel with a 1-in-7" rifling twist; improvements to the furniture, sights, and magazine; and a "permanent cure" for left-handed shooters being struck by ejected cases.

August: The Naval Surface Warfare Center (NSWC) - Dahlgren releases "Improved M16A1 Rifle Instrumented Tests and Results," the results of their testing of a pair of M16A1 rifles equipped with heavy barrels and improved forearms. Two standard M16A1 are used as control. Despite all four weapons being equipped with 1-in-12" twist barrels, the rifles using heavy barrels show superior accuracy in both automatic and semi-automatic fire. The experimental rifles are also considered to have superior handling qualities. In temperature testing, the improved round forearms are found to be cooler than their original counterparts, regardless of whether the handguards are installed on heavy or standard barrel rifles. Of course, the combination of the heavy barrel and round forearm gave the best results.

September:
The Mellonics Systems Development Division publishes "Adequacy of M16A1 Rifle Performance and Its Implications for Marksmanship Training." The document reports firing test results for typical M16A1 rifles, providing data for simplified and improved marksmanship training procedures. Sixty rifles were selected at random and subjected to bench-type serviceability checks and accuracy firing tests. Following initial testing, a representative sample (good, average and bad) of nine rifles was selected for the following tests: zero procedures, zeroing with the long range sight, trajectory, rimfire adapter, effects of barrel stress, firer error, and firing by initial entry soldiers. The current zeroing procedure is confirmed as being correct. However, the rimfire adapter is considered to be inadequate for attaining a correct zero and results in an increase group size. The authors also conclude that external stresses on the rifle (hasty slings, bipod use) actually have a greater effect on POA/POI errors than the usual culprits such as sight misalignment.

November:
The US Army Combined Arms Center (USCAC) and TRADOC approve the USAIS' recommendations for M16 improvements.

November:
The USAF's Systems Command indicates that they were not adverse to product improvements, as long as they did not require modification or replacement of their existing M16 rifles.

December: The USMC approves a "statement of need" for an improved rifle. However, a product-improved M16A1 would satisfy their immediate requirements.

**************************************************
1981...

With the approval of a joint service Rifle Product Improvement Program, fifty experimental M16A1(PIP) are ordered for testing. These rifles are later designated M16A1E1. These rifles include requested improvements such the 3 round burst mechanism, strengthened materials for the butt stock and forearm, a longer buttstock, the improved round/symmetrical forearm, a tapered slip ring for retaining the forearm pieces, a heavy profile barrel with a 1 in 7" twist suitable for XM855 and XM856 cartridges, and a fully adjustable 800m rear sight. Ironically, Colt had developed many of these improvements during the '60s and '70s.

January:
JSSAP publishes "JSSAP Combat Rifle Study." For the short term, JSSAP recommends staying on the course of the Rifle Product Improvement Program, which was already beginning to take shape. For the long term, JSSAP recommends that the technology base should be developed in areas such as salvo weapons, caseless ammunition, and advanced optics. Truly revolutionary improvements would have to wait until the year 2000 and beyond.

November: Colt delivers fifty M16A1E1 for testing.

November-December: As the lead service for the program, the USMC Firepower Division at Quantico conducts a "Modified Operational Test" pitting 30 M16A1E1 rifles against 30 standard M16A1. Twenty Marines and 10 troopers from the Army's 197th Infantry Brigade participate.

*******************************************************
1982...

Under Secretary of the Army James R. Ambrose endorses a potential 10-12 year rifle development program, which leads to a new Future Rifle Program and the eventual Advanced Combat Rifle (ACR) program.

At Picatinny, Vince De Siena and Major Dave Lutz (USMC) machine off the carrying handle of a M16A1 upper receiver, affix a commercial Weaver scope rail, and then mount a Kahles 1.5x optic. MAJ Lutz begins shopping the idea around a possible addition to the list of features for the M16A1(PIP). (Lutz also believes that this prototype may have been the genesis of the later Canadian flat-top project, due to his sharing an office with the Canadian Army Liaison Officer to JSSAP, Major Rick Wilson.)

The DOD expresses initial interest in a M16A1(PIP)-based carbine.

April:
The USMC's Firepower Division releases "Final Report: Test Results, Analysis, and Recommendations of Testing Conducted on the M16A1E1 Service Rifle." Not surprisingly, the Marines are very pleased since the rifles were effectively made to order.

September: The M16A1E1 is officially type-classified as the M16A2.

December: The Mellonics Systems Development Division based at Fort Benning publishes a rebuttal to the USMC's adoption of the M16A2. Fault is found with nearly every change made, even the decision to modify the rate of twist for the use of XM855 and XM856 ammunition. Another bit of nit-picking decries the lack compatibility of the 1-7" twist for use with the M261 .22LR conversion unit.

**************************************************************
1983...

Colt, on behalf of JSSAP's Future Rifle Program, begins work on a flat-top M16A2. (This is not the first time that Colt has built flat-top M16-type rifles. In the '70s, Colt produced a pair of prototype sniper rifles: the M16A1 Special High Profile (RO655) and the M16A1 Special Low Profile (RO656). The 'High Profile' mounted its optics to the carrying handle while the 'Low Profile' was of a flat-top configuration. Colt engineer Henry Tatro was involved in both the early and current projects.)

June:
Rock Island Arsenal employee, Loren Brunton files a patent application for the design of a M16 upper receiver incorporating an improved case deflector.

October:
Colt's Seth Bredbury and Harold Waterman, Jr. file a patent application for the new M16A2-type forearms. Waterman also files a separate patent for the M16A2's improved buttstock.

November: The M16A2 is adopted as Standard 'A'. The USMC places an initial order for 26,028 rifles.

***************************************************
1984...

January:
The first 1,500 M16A2 rifles are delivered to the USMC Marksmanship Training Unit at Quantico for use in matches. Grumbling arises from Marine competitive shooters about the negative effects of the 3 round burst mechanism upon the consistency of trigger pull weight in semi-auto use.

April:
The flat-top M16A2 rifle project is relabeled the M16A2 Enhanced Rifle, or M16A2E1.

June:
The USMC and Colt sign a follow-on contract for 50,364 M16A2 rifles.

September:
Colt is awarded a third contract for 63,188 M16A2 rifles.

Colt holds a meeting to begin development of a M16A2-based carbine, what will later become the XM4.
**************************************************

1985...

The Army orders 50 M16A2E1 rifles for use in testing experimental sighting devices. Oddly, the Army has yet to order any standard M16A2 rifles for issue.

Colt develops a new plastic collapsible stock to replace the original aluminum model.

January:
Aberdeen's HEL publishes "An Evaluation of the Hitting Performance of the M16A1 Rifle with and without a Sight Rib." A field evaluation was conducted of a sight rib designed by the report's author to improve the pointing qualities of the M16A1 and M16A2 rifles. The sight rib is an integral part of a new upper handguard and bridges the space between the front sight assembly and the carrying handle. It is parallel to the rifle bore and creates a strong visual cue as to where the barrel is pointing. Past firing tests have indicated that such a cue would improve a shooter's ability to hit targets quickly when there is insufficient time to aim properly. Twenty seven combat arms riflemen participated in the evaluation. They fired at pop-up E silhouettes emplaced in a fan at both 30 and 75 meters. The targets were presented for 2 and 3.5 seconds. Both range and exposure time were varied randomly. The test participants fired with both standard and sight rib equipped M16A1rifles using both aimed fire and pointed fire techniques. Time to fire and hit or miss data were gathered for each target presentation so that the data could be graphed to show the cumulative percentage of targets hit as a function of time. The results indicate that the sight rib on the M16A1 rifle significantly improves the soldier's ability to hit a target when the target is exposed briefly or the shooter fires quickly.

March:
Colt informs the Army that it is adding the M16A2-based carbine to the 1967 TDP and Licensing Agreement.

April: Colt delivers M16A2E1 rifles to the Army for testing.

June:
Colt is awarded a contract for 40 XM4 carbines for military testing.

August: Colt is awarded another contract for 116,722 M16A2.

December:
Colt's Henry Tatro files a patent application for the new double heat shield forearms for the XM4.

**************************************************
1986...

February:
Colt delivers 40 XM4 carbines to Picatinny. The carbines are not yet equipped with the double heat shield handguards.

The Mellonics Systems Development Division based at Fort Benning publishes "Analysis of M16A2 Rifle Characteristics and Recommended Improvements." It is in many ways a rehash of their December 1982 "Memorandum of Understanding." The characteristics of the M16A2 rifle developed by the Marine Corps were analyzed to determine what impact the new rifle's features would have on Army marksmanship training and on combat effectiveness. It was found that use of the M16A2 rifle by the Army would be extremely problematic, due in part to the vast differences between the marksmanship training philosophies of the Army and the Marine Corps. Numerous recommendations are presented, which could result in simplified training and improved combat performance if adopted.

March:
The Army announces their first major order for the M16A2, totaling 100,176 rifles.

Loren Brunton files another patent application for the design of the M16A2 upper receiver, which incorporates an improved case deflector.

April: TECOM starts the XM4 Carbine program with a direct entry into Development Test / Operational Test II. The USMC is the first to standardize the M4, with the goal of issuing them to their Special Operations Capable (SOC) units then under development. Reportedly, the only compact shoulder weapons authorized for use by Force Recon to this point has been the M3A1 SMG (bolstered by very unofficial use of XM177E2). Unfortunately, procurement funds for the Marines' carbines are killed during Congressional review in following budgets, and the matter is eventually dropped until the 1990s. In the mean time, the M3A1 are replaced by HK MP5-N received from the Navy.

Colt makes delivery of double heat shield handguards for the XM4 under evaluation.

Summer:
Diemaco's Phil O'Dell and Ian Andersen visit Colt to examine a Henry Tatro-designed M16-LMG. Diemaco has been considering the possibility of producing the design in a joint effort. They eventually decide to do so.

August:
Loren Brunton receives US Patent #D285,236 titled "Rifle Receiver."

November:
US Army frontline units receive their first M16A2

December: Diemaco conducts a function and tolerance study of the M16-LMG's firing mechanism. Colt has sent one of their prototypes for reference.

************************************************************
1987...

February: Colt begins working with a FATS simulator to test different sighting systems for their ACR.

March:
Diemaco completes development of the M16-LMG.

April:
The design of the M16-LMG is frozen at Colt to allow Diemaco to produce 12 pre-production units. These prototypes are sent to Colt for further testing during the summer.

May:
Colt's Henry Tatro receives US Patent #4,663,875 titled "Rifle Handguard Assembly Having Outer Shell with Outer and Inner Liners."

September:
Colt publishes the report "XM4 Carbine Development Program."

Loren Brunton receives US Patent #4,691,615 titled "M-16 Rifle, Improved to More Safely Accommodate Left Handed Shooters."

Late:
Diemaco and Colt begin series production of the M16-LMG. Diemaco is responsible for the upper assembly, some of the fire control parts, and the hydraulic buffer. Colt is responsible for the lower receiver, final assembly, and final testing.

November:
During an In-Process Review of the ACR project, Colt makes the decision to forego 2 and 3 round burst devices in favor of full-automatic fire.

************************************************************
1988...

Diemaco begins production of flat-top upper receivers.

March:
Joseph C. Kurak, on behalf of R/M Equipment, receives US Patent #4,733,489 titled "Apparatus for Reconfiguring Automatic Rifle to Include Grenade Launching Function."

May:
The DOD issues an open solicitation for M16A2 construction over a five-year contract.

September:
FNMI is awarded a five-year contract for M16A2 production. This comprises a total of 266,961 rifles.

Late: Brunswick begins a company funded NDI qualification of the Rifleman's Assault Weapon (RAW). The RAW is bowling ball-shaped, rocket-propelled grenade fired from a device attached to the muzzle and bayonet lug of a M16.

***************************************************************
1989...

February:
Colt completes assembly of the first six Phase III ACR prototypes.

March:
Colt submits their Phase III ACR prototypes to Aberdeen.

April:
The five submitted ACR designs are narrowed to four by Aberdeen's Combat Systems Test Agency. The remaining four candidates are then cleared for the 9 month field experiments at Fort Benning. Colt's ACR is most the conservative, being merely a flattop M16-variant with an improved hydraulic buffer, a more ergonomic collapsible stock, and the muzzle brake/compensator/flash hider assembly designed by Reed Knight. The oddest addition is the forearm, featuring a tall sighting rib inspired by the earlier HEL tests. The Colt ACR is submitted with an Olin-designed duplex 5.56mm load. The two projectiles weighed 35 grains (front) and 33 grains (rear), giving a velocity of ~2900fps. The rifle retains the ability to use the issue M855 cartridge.

May:
Colt conducts final test firing of their Phase III ACR prototypes. The final fifteen rifles are then submitted for the ACR field trials.

July: Colt begins training the military trainers assigned to the ACR field tests.

August:
Richard Swan of A.R.M.S., Inc. is shipped a sample of the Colt ACR's upper receiver and forging along with a purchase order for reengineering the upper receiver's scope rail. One of the main goals is to increase the strength the rail, as the existing rails cuts make the receiver too thin. (Reportedly, Swan demonstrated to Colt's Robert Roy that he could pierce the receiver at the bottom of the cut using the point of a Number 2 pencil.)

October:
The DOD begins a refurbishment program to update M16 and M16A1 rifles to the current M16A2 standard.

December:
A 6,000 round endurance test is run on the ACR candidates.

*************************************************************
1990...

The Weapon System Management Directorate at Rock Island Arsenal conducts a Fielded Systems Review of the M16A2. For the most part, the rifle is well received. They are complaints however about the 3 round burst feature, and the accuracy of the M855 and M856 cartridge.

August:
The ACR field trials end.

August 1990:
Colt and A.R.M.S., Inc. sign a non-disclosure agreement relating to their improved flat-top rail design. Oddly, the final design does not match the dimensions of Swan's earlier rail designed for the Canadians.

********************************************************
1992...

The Army announces that the ACR trial candidates have all failed to provide the required 100% improvement over the M16A2.

The US Navy SEALs begin issue of the M16A3, an M16A2-style rifle with full automatic capability instead of 3 round burst. (Note: The Navy's M16A3 is not the same configuration as Colt's "M16A3," which simply indicates a flat-top M16A2-type rifle.)

Colt commercially introduces their flat-top receiver for rifles and carbines. These are commercially designated the M16A3 and M4A1 respectively. (However, these weapon's features should not be confused with those of the military type-classified weapons using the same designation.)

Colt also unveils the 'CQB Carbine', equipped with a single rail adapter system for the attachment of the M203, a breaching shotgun, or other accessories. Colt also introduces the M203H, a stand-alone adapter for the existing M203.

**********************************************************
1994...

February:
USSOCOM awards Colt a contract for the production of 5,000-6,000 M4A1.

August:
The US Army officially adopts the M4 and M4A1 Carbines. Colt is awarded ~$11 million for 24,000 carbines. Only the first lot of M4 will be delivered with fixed carrying handles. Afterwards, all M4/M4A1 in inventory will be shipped with flat-top upper receivers.

September:
ARDEC publishes "External Barrel and Handguard Temperature of the 5.56mm M4 Carbine." This test report examines the external barrel temperature of the 5.56mm M4-series carbines as a function of time and as a function of longitudinal location on the barrel. It also compares the effects of the handguard on barrel temperature and measures the temperature of the M4 Carbine handguard external surface and internal liners.

************************************************
1995...

February: MIL-STD-1913 is approved, providing a standard for accessory/scope rail dimensions.

March:
ACALA issues a solicitation for 24,144 M16A1 Modification Kits. The kits will be used to upgrade existing M16A1 to the current M16A2 standard.

April:
ACALA awards FNMI a $6,955,520 contract for production of the M16A2.

August:
NSWC-Crane requests copies of the M4A1 TDP from ACALA. The TDP is needed in support of the SOPMOD kit.

September:
Rock Island Arsenal, on behalf of ACALA, responds to NSWC-Crane that it does not have a copy of the M4A1 TDP.

ACALA awards Capco, Inc. a $5,728,164 contract for 24,144 conversions kits to upgrade existing M16A1 rifles. The kits are earmarked for the USAF and USCG. There were 65 bids solicited, and five bids were received.

November: NSWC-Crane personnel directly call an ARDEC engineer at Rock Island Arsenal requesting the M4A1 TDP.

************************************************************
1996...

January:
The ARDEC engineer authorizes the release of the M4A1 TDP to NSWC-Crane. However, the TDP is not yet complete.

ACALA issues a solicitation for 29,667 M16A2.

July:
ACALA issues a sole-source solicitation to Colt for 9,785 M4 Carbines.

August:
ACALA awards FNMI a $11,840,880 contract for the production of 88,500 M16A2 rifles.

ACALA issues a sole-source solicitation to Colt for 9,785,716 M4 and M4A1 Carbines.

The ARDEC engineer releases additional drawings from the M4A1 TDP to NSWC-Crane.

September:
NSWC-Crane sends out Non-Disclosure Agreements to the 20 other contractors who received the M4A1 TDP. FNMI fails to sign and return the NDA.

ACALA cancels their previous solicitation for 9,785,716 M4 and M4A1 Carbines. The solicitation is corrected to add 716 M4A1 Carbines to a July solicitation for 9,785 M4 Carbines. FNMI submits a unsolicited proposal for the contract, which is rejected. ACALA then awards Colt a $5,510,617 contract for the production of 9,861 M4 and 716 M4A1 Carbines. FNMI in response files a protest to the GAO.

October:
ACALA cancels Colt's $5,510,617 contract for M4 and M4A1 Carbine production. Colt notifies ACALA that it should not have released the M4A1 TDP to NSWC-Crane, and that NSWC-Crane has breached Colt's licensing agreement by releasing the TDP to other contractors. The Congressional delegation from Connecticut requests a DOD audit of the Army and Navy's handling of the M4A1 TDP, and the decision to cancel the before mentioned contract.

December:
Colt notifies the Government that the failure to adequately to protect Colt's proprietary data constitutes a material breach of the 1967 Licensing Agreement. Thus, Colt announces the Government that the licensing agreement is terminated, and that the Government will no longer be permitted to use the data in the procurement and/or manufacture of the M16 and M4 family.

ACALA issues a sole-source solicitation to Colt for 1,012 M4A1 Carbines.

*****************************************************
1997...

The USAF begins to convert older M16 rifles to a M16A2-type configuration using modification kits.

The final "M4 Carbine Production Engineering Report" is released.

January:
ACALA awards Colt a $527,252 contract for M4A1 Carbine production.

February:
The Government acknowledges that Colt might be entitled to damages because of the unauthorized release, but disputes that the licensing agreement had been materially breached. Relying on Article XX of the licensing agreement, the Government asserts that a breach would arise, and termination would be appropriate, only in the event that the Government failed to use its best efforts to remedy the violation. Because it had presumably corrected its error by recovering all copies of the TDP from the Navy, and by securing non-disclosure statements from 19 of the 20 contractors (FNMI merely provided a letter attesting that it had not improperly used the data), the Government maintains that it had met its obligation under the licensing agreement. Therefore, the 1967 Licensing Agreement should remain intact.

ACALA awards Colt a $932,069 contract for M4A1 Carbine production.

April:
ACALA issues a sole-source solicitation to Colt for 2,031 M4A1 Carbines.

ACALA awards Capco, Inc. a $5,094,384 contract option for the manufacture of 24,144 M16A1 Modification Kits. 65 bids were solicited, and five bids were received.

May:
ACALA awards Colt a $1,058,151 contract for M4A1 Carbine production.

ACALA also issues a sole-source solicitation to Colt for 80 M4 Carbines.

June:
The DOD's Inspector General files an audit report on the issue of the M4A1 TDP release. It concludes that both the release of the data to the Navy, and the Navy's distribution to contractors, were improper. The Inspector General recommends that procedures be implemented to better safeguard Colt's proprietary data.

ACALA awards Colt a $41,680 contract for M4 Carbine production.

July:
The M16A2E4 (AKA: M16A4), the XM4 and XM5 Rail Adapter Systems (KAC's RAS for the M4 and M16), "Sight, Reflex with Mount, M68," "XM145 Telescope" (a variant of the ELCAN C79), and M203A1 grenade launcher are all type-classified. The XM145, later renamed the M145 MGO (Machine Gun Optic), is intended for use on the M249 and M240B. The M203A1 is designed for use on the M4 carbine.

In a letter to the Army, Colt estimates damages between 43.5 and 70 million dollars from the improper release of M4A1 TDP.

August:
ACALA issues a sole-source solicitation to Colt for 268 M4 Carbines.

The US Navy approves a Material Needs Statement from the SEALs for a new 5.56mm LMG. The goals include a weight under 13lbs, SOPMOD kit compatibility, and high corrosion resistance.

September:
Colt and the Army hold settlement negotiations regarding the M4A1 TDP release.

ACALA awards Colt a $139,628 contract for M4 Carbine production.

Colt's Laurance Robbins files a patent application for an improved gas block/front sight housing.


October:
ACALA issues a sole-source solicitation to Colt for 24,000 M4 and M4A1 Carbines spread over a four-year period. Later in the month, ACALA awards Colt a $3,126,000 contract for M4 and M4A1 Carbine production.

ACALA also issues a sole-source solicitation to Colt for 3,143 M16A4 Flat Top Upper Receiver and Barrel Assemblies.

ACALA issues a solicitation for 59,370 M16A1 Modification Kits over a three-year period. The kits will be used to upgrade existing M16A1 to the current M16A2 standard.

December:
Colt and the Army reach a final agreement, referred to as the "M4 Addendum." The "M4 Addendum" is comprised of two parts: the first characterizing the Army's rights for the M4 TDP, and the second clarifying of the status of the M16 licensing agreement. With regard to the M16 rights, the Addendum reaffirms the status quo set forth in the 1967 Licensing Agreement. This means that the terms of the 1967 license essentially will remain in place with Colt neither pursuing its multi-million dollar damage claim, nor maintaining its position that the license was terminated in light of the alleged breach. As to the M4 data rights, the Addendum grants the Government a non-exclusive, non-transferable, limited rights license for the M4 TDP that precludes the Government from using the M4's TDP in competitive procurements until the year 2011 (one source claims 2009). Afterwards, royalties will still be due until the year 2050.

************************************************************
1998...

The US Army announces its intent to gradually replace the M16A2 with a flattop M4 carbine equipped with the M4 RAS. (Some sources indicate that this variant was initially known as the M4E2.)

Modification Work Order (MWO) 9-1010-221-30-1 mounts the M203 on the M4/M4A1 and reclassifies the launcher as an M203A1.


January: NSWC-Crane announces its intent to purchase nine 5.56mm Light Machine Guns. The weapons must weigh between 9 and 14 pounds, with a firing rate of 700+ rounds per minute.

ACALA issues a sole-source solicitation to Colt for 75 M4A1 Carbines.

February:
ACALA awards FNMI a $12,621,672 contract option for the production of 31,700 M16A2 rifles.

March:
ACALA issues a sole-source solicitation to Colt for 15,925 M4 and M4A1 Carbines.

ACALA issues a solicitation for 6,497 to 32,402 M16A4.


April: ACALA awards FNMI a $3,233,855.52 contract option for M16A2 production.

The M4 and M5 RAS are standardized.

May:
ACALA awards Colt a $8,296,925 contract for the production of 15,925 M4 and M4A1 Carbines. The following day, FNMI delivers a proposal claiming that they are also capable of producing the M4 for the Army. The Army rejects the proposal for being late based upon the date the solicitation was filed on the Internet. However, the submission would have been on time based upon the date that the printed version was filed. FNMI, in response, files a lawsuit with the US Court of Federal Claims

June:
ACALA awards Colt a $18,148,960 contract for 88,037 conversion kits to upgrade existing M16A1 rifles.

ACALA also awards Colt a $2,514,339 contract for M16A4 production.

The US Court of Federal Claims denies the Government and Colt's motion to dismiss FNMI's suit. The Government and Colt's lawyers argued for dismissal on the basis that FNMI's submission was late.

July:
The US Court of Federal Claims rules that FNMI did not submit sufficient evidence that it could produce the M4 carbine within the time constraints of the solicitation.


October:
The US Court of Federal Claims rules that neither 10 USC 2320, nor the "Competition in Contracting Act," 10 USC 2304, prevents the Government from entering into a settlement agreement relinquishing rights in technical data if the data was developed at both public and private expense, and if a reasonable assessment of litigation risks reveals that the rights at issue are legitimately in dispute. Thus, the government had the right to recognize that the M4 TDP belonged to Colt outside of the 1967 License, and in settling its dispute with Colt, the government had properly entered into the "M4 Addendum." Therefore, the "M4 Addendum" did not violate the CICA, and was fully valid and enforceable. Based on the this, FNMI's action for injunctive relief was denied, and its complaint dismissed. FNMI did not appeal.

*************************************************************
1999...

After more than a decade of wrangling, USMC Force Recon, Fleet Antiterrorism Security Teams (FAST), and Military Police Special Response Teams finally receive their long awaited M4A1 Carbines, dubbed the Close Quarter Battle Weapon (CQBW).

The M4 and M5 RAS, the M16A4 rifle, and the M995 AP cartridge are all approved for full materiel release.


January:
The first M16A4 are issued.

ACALA awards Colt a $6,371,568 contract option for the production of 16,464 M16A4 rifles.

March:
ACALA issues a sole-source solicitation to Colt for 300 M4 and 9,000 M4A1 Carbines.

May:
ACALA issues a solicitation for 55,262 to 122,500 M16A4 rifles over a five-year contract period.

The SOPMOD Program Management Office (PMO) receives a directive from the commander in chief of USSOCOM (USCINCSOC) and Program Executive Office - Special Programs (PEO-SP) to study and improve the basic M4A1 Carbine platform.

July: The SOPMOD PMO begins fielding of M4A1 Extraction Parts Set #1 (EPS-1) to Navy and Air Force units.

September:
TACOM issues a solicitation for 13,757 M16A1 Modification Kits. The kits will be used to upgrade existing M16A1 to the current M16A2 standard. The solicitation is limited to Colt, FNMI, and Saco. Later in the month, FNMI is awarded a $2,737,643 contract for the requested number of kits.


October:
TACOM awards FNMI a $357,603 contract option for the manufacture of 1,797 M16A1 Modification Kits.


December: TACOM awards Colt a $135,716 contract option for 259 M4A1 with improved buttstocks. These are intended for delivery to the Navy.

***********************************************************

2000...

The NSWC-Crane begins work on the Close Quarter Battle Receiver (CQBR), a Colt "Commando"-sized, upper receiver fitted with a KAC M4 RAS. These are intended for use on M4A1 carbine lowers.

January:
TACOM awards Colt a $2,836,412 contract option for 5,413 M4 with improved buttstocks.

February:
TACOM awards FNMI a $1,011,381 contract option for the manufacture of 5,082 M16A1 Modification Kits.

March:
The Marine Corps Systems Command (MARCORSYSCOM) issues a solicitation for production and integration of a M4 Carbine Modular Weapon System. MARCORSYSCOM intends to negotiate on a sole-source basis with Colt to fill the requirement.

May:
TACOM awards FNMI $6,584,663 of a $49,972,650 contract for the production of 14,835 M16A4. Ten bids had been solicited, and five bids were received.

TACOM issues a solicitation for 2,615 M16A1 Modification Kits. The kits will be used to upgrade existing M16A1 to the current M16A2 standard. The solicitation is limited to Colt, FNMI, and Saco.

TACOM issues a sole source solicitation to Colt for 1,000 heavy replacement barrels for use with the M4.

July:
TACOM awards Colt a $400,408 contract option for 699 M4A1 with improved buttstocks. These are intended for delivery to the Navy and INS. Later, TACOM swaps an order for 3,240 M4 to an equal number of M4A1 with improved buttocks and heavy barrels. These are intended for USSOCOM.

The Army's Squad Designated Marksman rifle program is approved as a SEP. Proposed by the USAIC, the rifle's design parallels those for the SOPMOD SPR.

TACOM-ARDEC issues a sources sought announcement for enhancements to the M4 Carbine that will provide measurable improvements in accuracy against individual targets out to 600 meters. Specific areas of interest include, but are not limited to: barrels (heavy, fluted, floating), match triggers, magnified optics with range estimation, 5.56 mm ammunition, muzzle devices, bipods, buttstocks and cheek pieces. This information is being requested in support of the Designated Marksman portion of the Interim Brigade Combat Team.

August:
TACOM increases the order for M4 Improved Buttstocks from 8,779 to 9,779.

NSWC-Crane issues a request for a set of mold tooling to produce a Government-designed collapsible buttstock for the M4 series carbine.

September:
NSWC-Crane, on behalf of USSOCOM, issues a market survey notice to identify sources for either a Carbine Reliability Parts Set (CRPS) for the M4A1, or an alternative Enhanced Carbine (EC) to replace the M4A1. Goals for either the CRPS and EC include: increased reliability, durability, corrosion resistance, ease of cleaning, lubricity/reduced friction; fully functional for a minimum of 15,000 rounds threshold, 30,000 rounds objective; functional reliability exceeding that of the standard M4A1 carbine at high and low temperature extremes as well as other hostile (sand/dust/dirt/mud/surf) environmental conditions. The EC if selected must be available with two different barrel lengths. The short (9-12") barrel will be used for Close Quarter Battle (CQB). The medium (14-15.5") barrel will be used for standard SOF missions. The EC's barrel must be free-floating.

October:
Formal testing of first generation SPR is conducted at Thunder Ranch.

December:
TACOM awards Colt a $622,871.04 contract option for 926 M4 and 130 M4A1 with heavy barrels. The carbines will be equipped with the Improved Buttstock if it is available in time. The carbines are intended for the USMC.

The Second Marine Division begins testing of the M4 MWS for possible adoption of the M4 throughout the Corps.

2001...

The Army begins major fielding of the M16A4 along with the M4 and M5 RAS.

Colt assembles a number M16-LMG with flat-top upper receivers, open-bolt mechanism, and selective-fire components for US military testing. These are dubbed the Colt Automatic Rifle, Colt AR, or simply CAR.

Early:
Construction begins of 100 second generation SPR for a Limited User Test (LUT).

January:
The requirement for Improved Buttstocks is completely removed from the July 2000 order of 3,250 M4A1 for USSOCOM.

February:
NSWC-Crane, on behalf of USSOCOM, issues a market survey notice to identify sources of COTS/NDI extended-life, high endurance barrels. Improvements are sought in materials, manufacturing process, high endurance coatings, and other unknown technologies. Of interest are barrels manufactured by the hammer/cold forging process with heavy/durable chrome or other resistant material plating of the chamber and bore. Also of interest are barrels that are geometrically and materially optimized for rapid cooling and elimination of barrel burst. Further interest exists in improvements in chamber, bore, and rifling designs that enhance endurance, reliability, and accuracy. These improvements must enhance accuracy performance, and extend barrel life to a threshold of 10,000 rounds, with an objective of 30,000 rounds, under multiple firing schedules. While the eventual goal is to obtain enhanced life barrels for several types of rifles, carbines, and machineguns, the comparative test effort will be based on M4/M16 series weapons. Barrel lengths are sought in three length categories: short (10 to 12 inches), medium (14 to 15.5 inches) and long (16.1 to 18 inches).

March:
TACOM awards Colt a $5,226,875.52 contract option for 9,978 M4. Later in the month, another option worth $309,912.96 is exercised for 389 M4A1 (70 are equipped with heavy barrels). The requirement for Improved Buttstocks is completely removed from the July 2000 order of 499 M4A1 for the Navy.

TACOM issues a solicitation for 90,000 M16A1 Modification Kits. The kits will be used to upgrade existing M16A1 to the current M16A2 standard. The solicitation is limited to Capco and FNMI.

April:
TACOM awards Capco, Inc. a $22,740,040.96 contract for 90,181 conversions kits to upgrade existing M16A1 rifles. These kits are earmarked for use by the USAF.

Due to problems in manufacturing the Improved Buttstock, the requirement for 200 improved stocks is removed from the INS order, and another 4,760 is deleted from the earlier standing order for 9,779 stocks.

June:
TACOM issues a sole-source solicitation to Colt for 6,182 M4 Carbines.

July: TACOM awards Colt a $4,018,300 contract option for 6,182 M4 Carbines.

August:
TACOM awards a $1,130,583.54 contract option to KAC for 3,946 M4 RAS and various MWS parts.

September: TACOM issues a sole-source solicitation to Colt for 2,000 M4 and M4A1 Carbines.

TACOM awards Colt an additional $630,840 contract option for M4 Carbine production.

October:
TACOM completely eliminates all standing orders for M4 Improved Buttstocks due to continuing production problems.
***************************************

2002...

Inspired by their SA80A2 refurbishment program, HK begins a detailed assessment of M16/M4 Carbine technical deficiencies.

The USAF awards a contract to Aimpoint for more than 20,000 CompM2 sights.

January:
TACOM awards Colt $1,551,960 for 3,240 M4A1 Reliability Enhancement Kits. These kits are to improve the performance of the 3,240 M4A1 with heavy barrels previously purchased for USSOCOM.

TACOM also awards Colt a $157,950 contract option for 243 M4.

March:
TACOM awards Colt a $86,450 contract option for 133 M4. These are intended for the USMC.

ARDEC announces its intent to procure 60 barrels and 150 bolts for the M16 Rifle/M4 Carbine Long Life Barrel Program.

April:
TACOM awards Colt a $76,840 contract option for 113 M4A1. These are intended for the Navy and USAF

NSWC-Crane, on behalf of USSOCOM, issues a CAA for vendors who can provide accessory parts and assemblies for performance improvements to the M16/M4-series rifles/carbines. Specifically required are Special Purpose Receivers (SPR) for both short and long range precision fire, with improved MIL-STD-1913 rail interfaces, as well as related improved weapons parts and assemblies. The latter improvements, listed in priority order of government interest, may include new and improved 1) magazines, 2) bolt assemblies/bolt carrier groups, 3) barrels, 4) upper receivers and upper receiver groups, 5) trigger, sear, and hammer sets, 6) ambidextrous weapon controls, 7) flip-up/spring-up front and rear iron sights, 8) front and rear pistol grips, 9) buttstocks, 10) bipods, and any other components of, or mechanical accessories to, the M16-series/M4A1 carbines, with the exception of the lower receiver.

NSWC-Crane also issues a solicitation for 40,686 boxes of Black Hills Ammunition 5.56mm, 77 grain long range SPR Ammunition.

TACOM awards a $284,648.50 contract option to KAC for 500 M4 RAS and various MWS parts.

May:
TACOM issues a sole-source solicitation to Colt for 25,764 M4 and 12,972,700 M4A1 Carbines.

TACOM also issues a sole-source solicitation to Colt for 2,300 heavy replacement barrels and 2,000 upper receivers for use with M4/M4A1 carbines.

TACOM-ARDEC and PM-Small Arms issues a requirement for Back-up Iron Sights (BUIS). The BUIS shall provide a 300 to 600 meter capability on the modular versions of the M4 Carbine and M16A4 Rifle.

June:
The SPR is type-classified as the Rifle, Special Purpose Mk 12 Mod 0 and Mk 12 Mod 1. The Mk 12-series are designated marksman rifles built by NSWC-Crane armorers. The upper receiver is a mix of military and commercial parts, which is then mated to a M16A1 lower. The Mk 12 Mod 0 is recognizable primarily from its Precision Reflex, Inc. (PRI) free-float forearm. The Mk 12 Mod 1 use a KAC free-float RAS forearm. The Mod 1 evolved from the earlier SPR/A and SPR/B, which varied primarily as to which Leupold Vari-X III scope was mounted (3.5-10x versus 2.5-8x, respectively). The current Mk 12 Mod 1 reportedly uses a Leupold 3-9x.

The issue ammunition for the Mk 12 SPR is the 5.56mm Special Ball, Long Range Mk 262 Mod 0 (using the 77 grain Sierra Match King). The Mk 262 is the end product of accuracy testing which started with 27 different commercial match projectiles. The projectile choice was eventually narrowed to three: the 73 grain Berger LTB (Length Tolerant Bullet), the 87 grain PRL (Powell River Laboratories), and the 77 grain Sierra Match King. Availability issues with the first two manufacturers resulted in the Sierra Match King being chosen. To date, Black Hills Ammunition is the sole source of the Mk 262 Mod 0; however, there are indications that Lake City will begin loading the ammunition. The Mk 262 Mod 1 will reportedly use either the 77 grain Sierra Match King or the 77 grain Nosler Custom Competition (formerly, the J4 OTM). The main difference will be the introduction of a cannelure. Use of the Mk 262 Mod 0/1 has since filtered down to other 5.56x45mm weapons in USSOCOM's inventory. The Mk 262 Mod 1 has also been adopted by certain USMC units for use in their M4/M4A1 Carbines.


TACOM-ARDEC issues a sources sought announcement to identify enhancements for the M4/M16 series of weapons. Specific areas of interest include, but are not limited to: 1) Reliability/Durability - bolt carrier assembly and upper receiver/barrel improvements - to reduce failures to feed/extract and increase the service life of these parts; 2) Accuracy - forward MIL-STD-1913 rail system with free-floating barrel (M203 and sling attachment to rail system), more consistent trigger pull, repeatable accessory rail mounts - to improve system accuracy at extended ranges for individual targets; 3) Survivability - reduced flash and IR signature, faster target acquisition/engagement - to reduce visibility and exposure time to enemy fire; 4) Ergonomics - ambidextrous controls, adjustable front/rear pistol grip geometry, buttstock cheek weld, folding/detachable front sights, balance/controllability, reduced weight, battery storage - to enhance soldier/weapon interface; 5) Maintenance - corrosion resistance, ease of cleaning, shot counter - to reduce/simplify maintenance requirements. No modifications to the standard lower receiver are anticipated.

TACOM issues a sole-source solicitation to Colt for the production of M4 and M4A1 Carbines.

TACOM orders nine M4A1 Reliability Kits for shipment to Picatinny Arsenal for further testing. The ECP for the Improved Buttstock is reincorporated into the contract for a total of 8,128 stocks.

July:
TACOM awards Colt a $18,468,365.60 contract for the production of 25,764 M4 and 300 M4A1 Carbines for the Army, USAF, and Foreign Military Sales (FMS).

August:
TACOM awards FNMI a $1,998,700 contract option for M16A2 production.

The M4A1 SOPMOD OCONUS Performance User Review and Special Purpose Rifle (SPR) Capabilities Upgrade Conference is held. The majority of users prefer the Mk 12 Mod 0 over the Mk 12 Mod 1 in part due to ergonomic reasons. In contrast, the SPR builders uniformly prefer the Mk 12 Mod 1 due to ease of construction. However, there are some disgruntled users, particularly in the SEAL community, who really wanted a lighter 16" barreled Recon/'Recce' carbine instead of a heavy, militarized match rifle.

September:
The USMC announces its intent to replace the M16A2 with the flattop M16A4.

TACOM issues a sole-source solicitation to FNMI for 5,000 M16A2 rifles.

October:
ARDEC awards Alliant Techsystems (ATK) with a contract modification to the XM29 OICW program. The 5.56mm NATO KE Module is to be developed further into the XM8 Lightweight Assault Rifle. The XM8 is intended to replace the M4 carbine for issue to the "Objective Force Warrior." The MWS equivalent for the XM8 is later titled the Multiple Attachment Point System (MAPS).

FNMI receives an initial USMC order for 4,264 M16A4 rifles.

November:
The USAF begins accepting delivery of flat-top M4 fitted with the M68 CCO to replace their stocks of M16/M16A2 rifles and GAU-5/GUU-5 carbines. (Note: The USAF's GAU-5 series started with the original XM177, and consists of three variants differing primarily in barrel length. The models are the GAU-5A, GAU-5A/A, and GAU-5P. (A GAU-5A/B, or more properly a GAU-5B/A, is referenced by one source, but its existence has not been confirmed.) The GAU-5P is the longest, equipped with a 14.5" barrel. Many of the older weapons were eventually converted to this variant when an individual weapon required rebarreling. Several years back (1997?), the GAU-5 still in USAF service were eventually upgraded with a 14.5" M4-configuration barrel using a 1-7" twist. These upgraded models were redesignated GUU-5P.)


December:
TACOM modifies its M4/M4A1 contract with Colt for a net increase of $1,212,568.72. Additional quantities are procured for the Army, while the USAF's order is slightly reduced.

2003...

All M4A1 procured by the DOD now come from the factory with a special heavy barrel installed.

January:
NSWC-Crane issues a RFI for a SOF Combat Rifle (SCR) to replace the M4A1 carbine. The design is to be modular, allowing for multiple caliber conversions and configuration modifications to match divergent mission needs. "Draft" Key Performance Parameters of the SCR include:

Requirements                      (Threshold)         (Objective)
Corrosion Resistance                 4 days             10 days
Mean Rounds between Stoppage             2,000          4,000
Mean Rounds between Failure             15,000        30,000
Accuracy (MOA)                  1.5 @ 300 meters     1 @ 400 meters
Effective Range
Point Targets                        500 meters      600 meters
Area Targets                         600 meters      700 meters
Life Cycle (time before overhaul)    15,000 rounds    90,000 rounds
Modularity
(Caliber)    5.56mm TBD   (7.62x39mm/5.45X39/6.8x43mm)
(Mission) Adaptable to SOF mission scenarios: CQB/OTB/General Combat/Long-range Precision fires.

TACOM awards Colt a $331,975.28 contract option for 364 M4 Carbines.

February:
TACOM awards Colt a $2,954,925.79 contract option for 3,113 M4 and 98 M4A1. A few days later, 3,846 M4 Carbines are added for $3,313,371.55. (Most of this batch is destined for the USAF. Later in the month, an additional 244 M4 are added for $224,477.56.

TACOM awards Colt a $15,735 contract for M4A1 Reliability Kit replacement parts. This comprises 750 H2 buffers and 3,000 improved extractor springs.

March:
LCDR Gary K. Roberts, USNR, provides a written brief to RADM Albert M. Calland, USN, Commander Navy Special Warfare Command. The brief titled "Enhancement of NSW Carbine & Rifle Capability" recommends converting all 5.56mm NATO weapons in SEAL inventory to the new 6.8x43mm SPC.

TACOM awards Colt a $1,984,677.98 contract option for 1,769 M4 and 470 M4A1.

April:
The SCR is relabeled the SCAR (SOF Combat Assault Rifle). Now, the desired level of modularity includes larger cartridge conversions such as 7.62x51mm and a proposed .338 Short Magnum. The 7.62mm NATO-length configurations would be known as the SCAR-H (Heavy), while the 5.56mm NATO-length configurations would be the SCAR-L (Light). As such, these variants would replace the KAC Mk 11 Mod 0, the M14, the Mk 12 SPR, the SPR-V/KAC SR47, the CQBR, the M16A3, and the standard M4A1. The threshold accuracy loss is 1 MOA @ 300m, with an objective of 0.25 MOA at the same range. The desired objective range for area targets is increased to 800 meters for the SCAR-L. Threshold ranges for the SCAR-H are 600m point and 800m area, increasing to 800m/1000m as the objective. Barrel lifetime is specified as 10,000/50,000 rounds with the objective MRBS and MRBF increased to 8,000 and 50,000 rounds respectively.

The Army's PM-SW intends to negotiate with USSOCOM's PM-SOF Weapons regarding a potential role within the SCAR project, up to and including becoming the lead PM Office. Ideally, the Army would like to combine the SCAR with the XM8 as a spiral development project.

The JSSAMP is updated for the fourth time. Near term goals (Next 8 years) include improvements to current "legacy" systems, along with development projects such as the XM8, the XM25 Airburst Weapon (ABW: a stand-alone version of the OICW's grenade launcher), and the XM29 Integrated Airburst Weapon (IABW: formerly the OICW). These entail the introduction of lightweight ammunition such as the polymer-case 5.56mm cartridges currently under development by Natec, integrated electronic systems such as combined thermal/image intensification optics and multi-function lasers, and improved warhead technology such as thermobarics for the 25mm HEAB munitions and the 40x46mm grenade (XM1060 Multipurpose).

Mid term goals (8-15 years) include ultra-lightweight ammunition, a family of lightweight weapons (most likely based on the XM8), steerable/course-correcting munitions, and further fire control improvements including target hand-off capabilities. The far term goals (15 years +) once again include directed energy systems, ideally with scaleable effects for Lethal and Non-Lethal applications.

TACOM awards Colt a $2,007,219.64 contract option for 2,173 M4 and 9 M4A1. Later in the month, an additional 2,173 M4 are added for $1,999,138.27.

The CF C7A2 update is assembled from the following parts: an Accuwedge, ambidextrous controls (charging handle/mag latch/selector switch), a C8 telescoping stock, green furniture, a one-piece gas ring, and the Diemaco Triad I, an accessory mount which clamps to the existing gas block/front sight base. The ELCAN C79 sight is also to be upgraded with a green cover, an upgraded mount spring, and replacement tritium inserts. The complete upgrade package is due for user testing late in the year.

May:
TACOM awards Colt a $411,095.27 contract option for 29 M4 and 414 M4A1. These are intended for the Army, USMC, and other Defense Agencies.


June:
The Dismounted Battlespace Battle Lab and the 82nd Airborne Division test four magnified optics for the M4 and M249 SAW, capable of use in both close quarters and at distances of more than 500 meters. The information gathered will be evaluated by the Directorate of Combat Development and be used to help establish the requirements for a Multi-Purpose Optic.

TACOM issues a sole-source solicitation to Trijicon for 1,088 4x32 ACOG scopes (TA01NSN).

Summer:
The US military finally accepts an improved extractor spring for the M4/M4A1 originally recommended during the carbine's initial development. Previously, the military did not want to introduce a new part different from that used in the M16A2.

July:
TACOM awards Colt a $21,918 contract for M4A1 Reliability Kit replacement parts. This comprises 1,300 H2 buffers.

NSWC-Crane notifies A.R.M.S. that its RIS II proposal has been determined unacceptable "due to operational unsuitability for each of the four (SIR) configurations proposed." The SIR models was deemed unsuitable on two counts: all four models raised the operator's line of sight, and none adequately provided for the mounting of the M203 grenade launcher free of the carbine barrel.

August:
LTC Matthew Clarke, Product Manager-Individual Weapons (PM-IW), announces an order of 200 XM8 for testing by TECOM.

TACOM awards Colt a $353,327.46 contract option for 378 M4 and 6 M4A1.

SCAR Industry Week is held. The following firms attend: Armalite, Inc., Colt's Manufacturing Company, Diemaco, FN Herstal, Heckler & Koch, Inc, Israel Military Industries Ltd, Knight's Armament Company, Lewis Machine & Tool Company, and Robinson Armament Company.

NSWC-Crane releases "Draft Performance Specification: SOF Combat Assault Rifle Light." The caliber conversion requirements for the SCAR-L have been removed in favor of optimizing the weapon for the use of 5.56x45mm ammunition. (The proposed caliber conversions, such as 7.62x39mm, are instead intended to be passed along to the larger 7.62x51mm SCAR-H.) The SCAR-L is to possess the ability to interchange barrels to create three basic sub-variants: a Close Quarters Combat (CQC) variant with a 9-12" barrel, a Standard (S) variant with a 13-16" barrel, and a Sniper Version (SV) with an 18-20" barrel. All of the barrels will be free-floating and interchangeable at the unit level (or user interchangeable as an objective). The barrel lifetime requirement has been increased to 15,000 rounds.

The Standard model will possess a multi-position collapsible or foldable stock giving an overall weapon length of 33.6" extended and 29.9" collapsed/folded (or less as an objective). It will weigh no more than 7.725 lbs unloaded (less than 6.6 lbs unloaded as an objective). The multiple-position collapsible/folding stock will carry over to the CQC, but the SV will be equipped with a fixed stock with limited adjustments for length of pull. They should use STANAG-4179 compliant magazines, but alternate magazine designs of similar size would be considered if they offered a significant improvement in reliability and durability. There is also an objective for a standard length, expanded capacity magazine, ideally offering an 60 round capacity. A large emphasis is placed upon totally ambidextrous controls and use. Bullpup designs are ruled out. Accessory rails are to be integral, and the bottom handguard rail needs to be able to withstand the launching of a 40x46mm grenade from an attached EGLM.


Remington reportedly begins 'full' production of the 6.8x43mm SPC.

TACOM awards Trijicon a $685,440 contract for 1,088 ACOG TA01NSN scopes.

TACOM awards Colt a $135,863 contract for M4A1 Reliability Kit replacement parts. This comprises 7,280 H2 buffers and 12,740 improved extractor springs.

September:
MARCORSYSCOM announces its intent to negotiate a sole source contract for 708 M4A1 Close Quarter Battle Weapons (CQBW) to support immediate Marine Corps Fleet Unit requirements.

TACOM awards Colt a $127,878.61 contract option for 139 M4. Later in the month, another 354 M4 are added for $309,827.88.

TACOM-ARDEC issues a RFI for COTS/NDI accessory shotguns which can meet the Army's needs with only minor modifications, or militarized 12 Gauge Shotguns that can function in both stand-alone and accessory capacities. The Accessory Shotgun shall be capable of attachment to the M4/M16 series of weapons and the Future Combat Rifle (FCR). It must use detachable magazines, weigh less than any current stand-alone shotgun, and maintain the ability to fire 2.75" and 3" lethal, non-lethal, and breaching ammunition. This shall be done without degrading accuracy, reliability, and durability of the weapon system (the accessory shotgun and the host weapon) from the baseline.

NSWC-Crane releases a pair of amendments to the MDNS solicitation. Revised proposals are requested from specific offerors for the RIS II and the ECOS-C.

After a pre-award debriefing for RIS II, A.R.M.S. files a protest with the GAO over the rejection of its four SIR models.

TACOM-ARDEC issues a solicitation notice for an upcoming Broad Agency Announcement (BAA) regarding the development and system integration of a Small Arms Lightweight Family of Weapons and Ammunition (LFWA). As the "lethality component" of the Objective Force Warrior (OFW) program, the LFWA program will initially focus on the development of a lightweight machine gun and ammunition. The primary goal is a reduction in volume and weight, ranging up to a 30 to 40 percent decrease over existing systems. The designs may use a "clean slate" approach with no concern given to backwards compatibility with existing weapons and ammunition. Two major demonstrations of the new LFWA system are currently planned. The first will be a non-firing demo in mid FY06 to support the OFW Advanced Technology Demonstration (ATD). The second demonstration will be an operational live-fire assessment, scheduled for late FY07. The program is projected to include three Phases: nine months for Phase 1, twenty-eight months for Phase 2, and five months for Phase 3. Down-select criteria may be used for either Phases 2 or 3 if multiple awards are made.

October:
USSOCOM issues a solicitation for SCAR candidates, followed later in the month by revised copies of "Draft Performance Specification: SOF Combat Assault Rifle Light" and "Draft Performance Specification: SOF Combat Assault Rifle Heavy." The barrel change requirement is modified to allow exchanging of complete upper receiver assemblies. The objective MRBF is reduced to 35,000 rounds, and the same figure is also given as the objective barrel lifetime. The maximum threshold weight for the SCAR-L is reduced to 7.25 lbs. The Standard SCAR-H model will possess a multi-position collapsible or foldable stock giving an overall weapon length of 40.2" extended and 30.3" collapsed/folded (or less as an objective). It will weigh no more than 9 lbs unloaded. Offerors will be required to provide product sample SCAR-Ls as part of their proposals, consisting of three standard SCAR-L rifles, one CQC conversion, and a SCAR-H technical approach. The due date for submissions is given as June 19, 2004.

Thirty HK XM8 Lightweight Modular Weapon Systems (LMWS) are delivered to Aberdeen. The Multiple Attachment Point System (MAPS) has since been renamed Picatinny Combat Attachment Points (PCAP).

TACOM issues a sole-source solicitation to Colt for up to 100,000 M4/M4A1 carbines.

The USMC announces its desire to issue the M4 carbine with MWS forearms to replace the M9 pistol and M16A2 rifles carried by personnel such as small unit leaders and vehicle crew members. However, the M16A4 will remain be the primary issue weapon for Marine riflemen. Based upon its experience in Iraq, the Corps also intends to issue a magnified Rifle Combat Optic (RCO) to all riflemen.

The long rumored 6.8x43mm Remington SPC (Special Purpose Cartridge) is finally unveiled to the public at the annual meeting of the Association of the US Army (AUSA). Intended for use in converted 5.56x45mm weapons, the 6.8x43mm SPC launches a 115 grain projectile at 2,650fps from a 16.5" barrel. As rumored, the case is derived from the .30 Remington (albeit in an even shorter form than the .224E4/E5 Winchester and the FA-T116 6.35mm SCHV.) Also introduced are drop-on M16/M4 upper receiver conversions for the 6.8mm SPC built by Barrett and PRI. Unfortunately, rumors do not pan out regarding unmodified 5.56mm magazines holding 28 rounds of the new cartridge. The latter is only achieved with replacement magazine bodies designed especially for the 6.8mm SPC.

December:
TACOM-ARDEC issues a pair of pre-solicitation notices regarding the XM8 Lightweight Assault Weapon System. The first regards design improvement efforts, including back-up iron sights, a visible bright light, a folding or collapsible buttstock, and an Automatic Rifle variant. The other concerns development and testing of seventy-two Safety Blank Firing Adapters.

TACOM-ARDEC later announces its intent to negotiate a sole-source contract with HK for 500 XM8 in four different configurations.

USSOCOM issues drafts of Section L (Proposal Requirements) and Section M (Evaluation Factors for Award) for the SCAR Performance Specification documents.

Later in the month, MARCORSYSCOM issues a combined synopsis/solicitation notice for the procurement of Rifle Combat Optics (RCO). Intended for the M16A4, the RCO will be fixed power optic in the 3.5 to 4.5x magnification range. Certain other requirements, such as the preferred reticule design, would appear to favor the Trijicon ACOG family. The prospective order is to fall between 3,000 and 10,000 units, filled over a period of three years.

The GAO sustains A.R.M.S.' protest over the rejection of its four SIR models from the RIS II competition. The ruling recommends that the SIR models be among the models considered for the contract award, and that A.R.M.S. be reimbursed for the costs of filing and pursuing its protest.

The US Army Robert Morris Acquisition Center, Natick Contracting Division, announces its intent to negotiate and award a sole source contract to Sure-Fire, Inc. for 110 Rifle Flashlights (M952XM06).
***********************************************************

2004...

January:
USSOCOM issues final Performance Specification documents for the SCAR-L and SCAR-H. An RFP is also issued.

TACOM awards Colt $11,260 for testing the suitability of the H2 buffer with M4 Carbines.

February:
HK formally introduces the HKM4 system, consisting of product-improved replacement parts for the M4/M16 family. The most distinct change is the introduction of a gas piston system to replace the direct gas impingement system used in the typical M4/M16. Retrofitted weapons will have the option of four different barrel lengths (10, 14.5, 16.5, and 20 inches), but HK is also considering the possibility of offering upper receiver units and even the construction of complete weapons.

TACOM awards a $984,175.92 contract option to FNMI for the production of 2,106 M16A4.

NSWC-Crane issues a sole-source solicitation notice to Colt for 100 M4A1 carbines and 100 CQBR.

USSOCOM amends the specifications for the SCAR-L and SCAR-H.

TACOM-ARDEC awards HK a $2,273,000 R&D contract for the XM8 Lightweight Assault Weapon System

TACOM-ARDEC also announces its intent to negotiate a sole-source contract with ITI to design and deliver 170 XM8 Visible Bright Light Flashlights. The VBL will be mounted to the XM8's PCAPs.

NSWC-Crane issues a combined synopsis/solicitation for 1,000 ambidextrous selector switches from KAC. The selectors are intended for use with the M4A1 carbine.

NSWC-Crane releases another amendment to the MDNS solicitation. Final proposal revisions are requested from specific offerors for the Miniature Night Vision Sight II (MNVS II).

March:
NSWC-Crane awards Litton Electro Optical Systems a $49,999,990 contract for Mini-Day/Night Sight (MD/NS) development.

USSOCOM issues a solicitation for 12 to 3,000 COTS Visual Augmentation System (VAS) In Line Clip-On Night Sights for long gun application up to and including .50 caliber. This will replace the Integrated Day/Night Fire Control Observation Device (INOD) AN/PVS-19 and the Universal Night Sight AN/PVS-22. It will serve as a bridge until technology has matured where a full material solution can be achieved, i.e., a family of sniper sights which will meet the requirements of the JORD addendum dated 25 June 2003. The desired Optimal Resolution is 4.2 cycles per milliradian or better. The in-line sight must interface with existing day scopes without having to adapt/modify existing scope rings, current day scopes, or shooters' firing positions. The system must also be able to mount on MIL-STD-1913 rails using a single throw lever type mounting system (KAC's PN: 22097 Knightscope base assembly) or equivalent.

NSWC-Crane, on behalf of the USMC, issues a sole-source solicitation to Litton Electro Optical Systems for a minimum of 1,056 AN/PVS-17B and 1,010 AN/PVS-17C Marine Corps Miniature Night Sights (MNS).

TACOM-ARDEC issues a market survey notice for a Close Quarters Battle Kit (CQB Kit) for use with the M16/M4. The kit will consist of the following items: 1) a compact cleaning kit; 2) a removable, spray-on weapons camouflage kit with a minimum of four colors; 3) a multiple magazine holder capable of holding two standard 30 round magazines; 4) an add-on forward Picatinny rail system with a minimum of three rails with one bottom- mounting rail; 5) an adjustable low profile bipod; 6) a stock-mounted magazine pouch; 7) a tactical sling; and 8) and an improved flash hider.

PM-Soldier Weapons issues a sources sought announcement for a Single or Three Point Sling for use with the M4 Carbine. The single point sling must provide ready access to the M4, with no sling repositioning necessary. It will attach the weapon directly to load bearing equipment and will allow the wearer to keep their weapon in a near-ready position while performing two-handed tasks. The three-point sling must provide with fast and easy transitions, free of tangling or twisting, and offer the individual soldier with custom positioning for weapon balance.

USSOCOM also announces its intent to include the EGLM as part of the SCAR solicitation. The contract will require a maximum of 21,000 EGLM, 25,000 fire control modules, and 25,000 stand-alone buttstocks.

April:
Colt Defense LLC files suit against Bushmaster Firearms, Inc. and HK in the US District Court for the Eastern District of Virginia. Related to the marketing of the M4 Carbine, Colt cites acts of trademark infringement, trade dress infringement, trademark dilution, false designation of origin, false advertising, patent infringement, unfair competition, and deceptive trade practices. Colt is seeking injunctive relief and damages against the two companies.

TACOM awards Colt a $123,035,995 contract for the production of 124,803 M4 and M4A1 carbines. The first delivery order for 22,435 M4 and 1,288 M4A1 is worth $21,373,067.00. These are intended for the Army, USMC, USAF, and FMS.

USSOCOM amends the specifications and the RFP for the SCAR-L, SCAR-H, and EGLM. SCAR contenders must now be submitted with an EGLM, fire control module, and a stand-alone buttstock.

The Army requests an additional $26 million from Congress to purchase 7,000 XM8. The Army wants to field the XM8 system with two combat brigade teams by September 2005. In related news, the XM8's "Milestone C" review (the prelude to a full-rate production decision) is pushed back from September 2004 to February 2005.

PM-Soldier Weapons issues a sources sought notice for a Red Dot Weapon Optic system to be used with the M4 MWS, M16A2, and M16A4. The device will be a non-magnifying, reflex sight with a 1 to 4 MOA red dot reticule and manually adjustable brightness settings. It will also contain an anti-reflection device to minimize glint, and be mountable on MIL-STD-1913 rail system. The optic must be able to withstand the rigors of use in a military environment and still maintain zero. Battery life must be comparable to current M68 CCO.

May:
NSWC-Crane issues a sole-source solicitation to Colt for 500-2,000 M4A1 carbines equipped with the CQBR. An additional 500-5,000 separate CQBR are also requested.

NSWC-Crane issues a sole-source solicitation to Trijicon for 218 Reflex Sights (RX01M4A1).

NSWC-Crane awards separate ECOS-C contracts to Canadian Commercial Corp. (ELCAN), EOTech, and Trijicon. The individual awards are worth up to $16,666,666 for a maximum of 66,666 ECOS-C apiece.

PM-Soldier Weapons issues a sources-sought notice for a COTS weapon optic system to be used with 5.56mm rifles. The optic must possess the following characteristics: approximately 4x32mm, allow target engagement out to 800 meters, integral ballistic correction for range without external adjustment, Day/Night illumination capability (without use of batteries but NRC exempt), an Anti Reflection Device, a Laser Filter Unit (or compatible to be fitted with Laser eye protection filters/goggles), MIL-STD-1913 rail system compatible, and able to withstand the rigors of use in a military environment.

June:
SCAR and EGLM candidates are submitted to USSOCOM for testing. No word as yet been released as to which vendors submitted products nor the products submitted.

July: $25.9 million budgeted for XM8 production is cut from a Fiscal Year 2005 Department of Defense appropriations bill. Reportedly, an additional $1 million was budgeted to HK for the production of polymer-cased ammunition.

TACOM awards a $1,614,822 delivery order to Colt for 1,707 M4 Carbines.

NSWC-Crane issues a sole-source solicitation to Insight Technology, Inc. for 13 AN/PSQ-18A M203 Day/Night Sights, 13 AN/PEQ-5 Carbine Visible Lasers, and 36 AN/PEQ-2.

NSWC-Crane issues a sole-source solicitation to KAC for 128 M4A1 QD Compensators and RIS forearms with vertical foregrips.

The Robert Morris Acquisition Center's Aberdeen Branch issues a sole-source solicitation to Insight Technology, Inc. for up to 16,000 Integrated Sighting Modules (ISM) and Advanced Magnified Optics (AMO). These will be used with the M4, M16, and XM8. The ISM is a 1x optical sight with integrated red dot and near infrared (NIR) aiming and fixed focus illuminating lasers. The red dot and the NIR lasers shall be co-aligned and shall adjust for azimuth and elevation using a common adjustment mechanism with no special tools. The AMO is a 4x magnification optical sight with integrated red dot and NIR aiming and variable focus illuminating lasers. The NIR aiming pointer on the ISM and AMO shall have a range of 600m in low power and 2000m in high power. Additionally, both sights shall utilize a common commercial battery (e.g., AA or 123.)

MARCORSYSCOM amends its earlier combined synopsis/solicitation regarding Rifle Combat Optics (RCO) for the M16A4. Later in the month, MARCORSYSCOM awards Trijicon a $7,500,000 multi-year contract for the Rifle Combat Optic (RCO). The RCO is a modified version of the TA31 ACOG scope.

August:
NSWC-Crane awards Litton Electro-Optical Systems and Insight Technology $24,999,999 apiece for the development of Clip-On Night Vision Devices.

September:
TACOM-ARDEC issues a market survey announcement to identify sources capable of providing a lubricous coating for critical small arms weapon components. This coating is desired to eliminate the need for wet lubrication. Currently, most weapon parts are steel coated with either hard chrome or phosphate and maintained with wet lubrication. This potential coating is expected to function without need for external lubrication in adverse conditions to include: sand, dust, extreme cold (-65 degrees Fahrenheit), extreme heat (400-800 degrees Fahrenheit), rain, mud, salt water, Nuclear/Biological/Chemical (NBC) decontamination solvents, etc. The maximum operating temperature is dependent upon the weapon component in question. The following characteristics should be addressed as to how they well they perform with respect to hard chrome and phosphate: 1) Corrosion protection; 2) Abrasive and sliding wear resistance; 3) Adhesion to substrate; 4) Coefficient of friction; and 5) Coefficient of thermal expansion.

ARDEC issues a sole-source solicitation to Colt for 63 M4A1 Carbines. Sixty will have a coating of Nickel Boride applied to the individual components of the weapon. The remaining three M4A1 Carbines will be manufactured and delivered using the current anodizing and phosphate coatings.

TACOM modifies its June 2004 solicitation to KAC for an additional 10,000 M4 RAS Upper Hand Guard Assemblies and 16,000 each M5 RAS Upper Hand Guard Assemblies.

October:
The National Small Arms Center issues a source-sought announcement for research proposals. The proposals cover three Research Areas: New Metal Coating Technology for Greaseless Weapons, Anti-Materiel Sniper Rifle (AMSR) and 5.56mm Polymer Cased Ammunition.

TACOM issues a solicitation notice for the procurement of Back Up Iron Sight (BUIS) for the M16A4, M4, and M4A1. A minimum of 6,000 units is guaranteed over a five year period.

November:
USSOCOM awards FN a $634,390 contract for the SCAR. The only info released by FN indicates that their weapon uses a short-stroke gas system and a metal receiver.

ARDEC issues a sources-sought announcement for a Non-Developmental, multi-configurable, 5.56mm modular weapon system. The system shall consist of four variants to include: Special Compact (SC), Carbine, Designated Marksman (DM), and Light Machine Gun (LMG). All variants need to function in both semi-automatic and automatic firing modes, with the LMG's primary firing mode being full auto. Other features include a Multi-Purpose Sighting System (MPSS) capable of precision fire out to the desired effective range of the weapon, yet fast enough to allow successful engagement of a 50m target within 1.5 seconds. Back-up sights are required which allow for the engagement of targets out to 300m without removal of the MPSS. In addition, the weapons shall include limited visibility fire control with an infrared aim light and illuminator. The weapons must be compatible with all standard 5.56mm NATO ammunition including the Mk 262 Special Ball. The weapons shall be ambidextrous with respect to: the selector switch, charging handle/forward assist, magazine release, and bolt catch. Furthermore, ejected cartridges must not be channeled to the rear as this can interfere with use by left handed shooters. The weapon must possess an adjustable stock which can accommodate all users between the 5th and 95th percentile in size. Minimum barrel life shall be no less than 15,000 rounds. The flash hider should minimize dust signature and act as a muzzle brake. It should also allow for a no-tools attachment of a sound suppressor. Attachment points are desired for the mounting of a 40mm grenade launcher or a 12 gauge shotgun. The LMG shall provide for a quick-change barrel capable of replacement in under 30 seconds while under combat conditions. The LMG barrel shall also provide the operator a visible means of determining cautionary heat levels. In a swipe at Colt's sole-source status for the M4 Carbine, data rights are demanded for the purpose of competitive bidding and second-source contracting.

TACOM announces a sole-source solicitation to KAC for an estimated 45,000 M4 Rail Adapter Systems, 44,125 M5 Rail Adapter Systems, 33,000 M203 Quick Release Brackets, and assorted small parts.

December:
At FN Herstal in Belgium, USSOCOM representatives conduct the first critical design review for the SCAR since the award of the contract. During a period of three days, the development team works side-by-side with Operators for an iterative design process. Operators test the weapons on the range to gauge the initial capabilities of the weapons which they had previously outlined in the requirements. The development team is then able to make immediate changes and improvements to prototypes and designs. Upon conclusion, FN delivers a modified mockup prototype within 24-hours based on the feed-back received. In addition, the first SCAR-H prototype is unveiled and tested. Based upon the progress made so far, the decision is made to condense and accelerate the program increments to the following: 1) Development of the SCAR-L (with integrated EGLM) and the SCAR-H for concurrent fielding; 2) Ensure EGLM compatibility; 3) Production of the SCAR in Enhanced Calibers as directed by USSOCOM and the Integrated Product Team. Development of the EGLM to use Fuse Programmable Ammunition; 4) Continue development of SCAR and EGLM capabilities.

NSWC-Crane announces changes to the RIS II specification. A rigid or monolithic interface system is desired which will allow for a free-floating carbine barrel, yet withstand the shock of firing all currently fielded 40mm rounds, and maintain zero repeatability when accessories are removed and remounted. While MIL-STD-1913 rails are still required, alternative intermediate or supplemental interfaces will be considered if they will allow the EGLM and other lower rail subsystems to be mounted as closely to the carbine barrel as possible without touching it. The solicitation is still limited to vendors who had previously submitted proposals for the RIS II.
************************************************


2005...

January:
TACOM issues a solicitation for 3,000 to 150,000 M16A4.

TACOM awards a $12,293,574 delivery order to Colt for 11,898 M4 and 638 M4A1 Carbines. These are intended for the USAF and the Army National Guard and Reserves.

General Dynamics European Land Combat Systems and HK announce the creation of a US-based joint venture company to manufacture and deliver the XM8.

RDECOM-ARDEC issues a sources-sought announcement for a COTS/NDI Magnified Optical Sight (MOS) for the M4, M16, and M249. The MOS must meet or exceed the following requirements: 1) The MOS shall be illuminated (unpowered or powered, unpowered preferred) and shall be effective in day and night situations; 2) The MOS shall provide a capability to estimate range and effectively recognize and engage targets from 0 to 600 meters during the day and 0 to 300 meters at night (when coupled with the AN/PVS 7 or AN/PVS 14); 3) The MOS must provide the capability to acquire targets using one and/or with both eyes open for rapid target acquisition and allow for rapid transition between long-range and close quarters engagements; 4) The MOS must allow for rough handling, and shall be able to be carried by the optic's body; 5) The MOS shall be able to maintain zero during operational modes in all environmental; and 6) The MOS shall contain a Laser Filter Unit or be compatible to be fitted with a Laser eye protection filter. The quantity required by the government is estimated to be 100,000.

February:
At FN Herstal in Belgium, USSOCOM representatives conduct the first critical design review for the SCAR. Two improved SCAR-L variants are tested (CQC and Standard, with the EGLM) along with the modified SCAR-H (CQC) prototype. The following aspects of design and testing are discussed:

A new pistol grip that improves the ergonomic fit
A front sight post with folding and locking options
Gas regulator settings
Barrel mounting screws
Stock adjustment controls
Rear sight adjustments
Modular butt plate features
SCAR-H testing data
Suppressor integration
EGLM ergonomic decisions
EGLM Fire Control System (FCS) decisions


Colt buys Diemaco for $16.5 million. Diemaco will be operated as Colt Canada Corporation.

TACOM awards a $9,009,140 delivery order to Colt for 9,193 M4 Carbines

PM-Maneuver Ammunition Systems announces its plans to research and select an optimum 'green' 5.56mm cartridge that meets performance requirements and is affordable.

TACOM awards $35,046,199.41 of a $47,530,000 contract to KAC for MWS components and assorted spares. An additional $6,650 is awarded later in the month.

NSWC-Crane announces that it will be accepting final proposal revisions for the RIS II. The announcement is still limited to vendors who had previously submitted proposals for the RIS II.

RDECOM, on behalf of the Army and USMC, issues a sources-sought announcement for COTS/NDI Multi-Functional Aiming Lights (MFAL). The Multi-Functional Aiming Light (MFAL) will give the Soldier/Marine the capability to employ an IR aiming laser/pointer and IR illuminator in a small, lightweight aiming light that is weapon-mounted or hand-held. Desired, but not required, capabilities are a visible aiming laser and/or white light illuminator. When weapon-mounted, MFAL will provide the Soldier/Marine a capability to accurately aim his weapon during periods of darkness when used in conjunction with an image intensification device such as the AN/PVS-7 or the AN/PVS-14. The MFAL will be employed with the following weapons: M16A1/A2/A4, M4/M4A1, modular weapons, M240B, and M249 (threshold), M136, M203, MK19 and M2 (objective), and must be able to mount on a MIL-STD-1913 rail using an interface device. The IR aiming laser/pointer will have a range of 600m in clear, quarter moon conditions (threshold), 2,000m (objective). The IR illuminator will have a range of 600m in clear, quarter moon conditions (threshold), 2,000m (objective) and illuminate a darkened room. If proposed, the visible aiming laser should be visible with the naked eye and have a minimum range of 25m in daylight (with daylight defined as that time between sunrise and sunset, but not in direct sunlight). If proposed, the desired white light illuminator should provide facial recognition at a range of 25m. Each laser will have a Non-Ocular Hazard Distance (NOHD) of 25m in low power for the unaided eye.


March:
ARDEC, on behalf of the PM-Soldier Weapons, issues a solicitation for the OICW Increment I family of weapons. The OICW Increment I family of weapons is intended to replace current weapon systems to include the M4, M16, M249 and selected M9 pistols for the active Army. This solicitation contains a restatement of the criteria laid out in the November 2004 Sources-Sought notice for a 5.56mm Modular Weapon System family. Competitors will need to submit four examples of each category for a total of 16 weapons. After satisfying a Milestone C decision, Low Rate Initial Production (LRIP) quantities of up to 4,900 weapons will be produced. Afterwards, multiple Full Rate Production (FRP) options may be award for up to 134,500 weapons total.

TACOM awards Colt a $787,538.77 contract for 700 M4 R0921 carbines, 3,500 spare magazines, and assorted spare parts. These are intended for the 10th Special Forces Group.

TACOM awards a $9,611,364 delivery order to Colt for 9,816 M4 Carbines. These are intended for the USMC and USAF. Later in the month, a $999,232 delivery order is awarded for 887 M4 and 200 M4A1 Carbines. Once again, the majority of these are intended for the USAF and USMC.

TACOM awards FNMI $6,691,046 of a $29,778,298 contract for M16A4 bolts, barrels, and receivers.

TACOM-ARDEC issues a solicitation for 3,180,608 to 25,549,925 M995 AP cartridges.

NSWC-Crane awards individual contracts worth up to $16,666,666 apiece to A.R.M.S., Daniel Defense, and KAC for the RIS II. Up to 92,877 RIS II apiece will be acquired from each company. Delivery Order 1 is for 5 Engineering Test samples and 10 additional for Operational Testing. These are the only quantities the Navy is obligated to buy from any one vendor.

April:
TACOM awards Colt a $980,000 delivery order to Colt for 1,000 M4 Carbines. These are intended for the USMC.

TACOM awards KAC a $283,620 contract option for 1,000 M4 RAS. These are intended for the 1,000 M4 Carbines ordered for the USMC.

TACOM awards a $90,976.27 contract to Trijicon for 121 ACOG TA01NSN optics. These are intended for the USAF.

Air Force Special Operations Command issues a solicitation for 60 EOTech Holosights (550 Military Model.)

RDECOM, on behalf of the Army and USMC, reissues a sources-sought announcement for COTS/NDI Multi-Functional Aiming Lights (MFAL). It repeats the requirements from the February 2005 announcement, and adds the following: The MFAL aiming lasers shall retain a zero position within 0.5 mrad after being subjected to the shock of one combat load (210 rounds/M855 ammunition) of the M4/M16 rifle. The MFAL must have dual activation controls: an on/off switch which shall be located on the device housing and a wired remote control switch which shall momentarily activate each of the functions (i.e., IR aiming mode and IR illuminator mode.) The device will weigh no more than 10 ounces with batteries installed (threshold), 8 ounces (objective). The Government may award one or more, contracts for 2,000 to 340,000 MFAL.

NSWC-Crane issues a sole-source solicitation to LMT for 688 CQBR Rear Sights.

Quoted: 1984... January: The first 1,500 M16A2 rifles are delivered to the USMC Marksmanship Training Unit at Quantico for use in matches. Grumbling arises from Marine competitive shooters about the negative effects of the 3 round burst mechanism upon the consistency of trigger pull weight in semi-auto use.

Damn JarHeads, always making trouble about one thing or another!

Quoted: That is the $64,000 question isn't it?  I can't think of any good reason for Colt to make the flattop sights .040" higher than the non-flattop sights.  Which is probably why everybody else like BM just uses the the same FSB on both.  But since it's Colt I guess we shouldn't be surprised.  Not after the big pivot pins, the sear blocks, the "C" bolt carriers, and the large trigger & hammer pins.

+1 Also, hasn't Bushmaster and others already proved that there is no need for the taller sights? The shorter flattop sights are in use everyday without any problems.

Quoted: Quoted: Quoted: Quoted: last time i looked at this thread, it was 2 pages.  I'm not going to go back and read through arguing.  So, I'll just ask, did anyone suggest that maybe Colt tried to throw other companies off by making a few minor changes when they introduced the flattop M4? Again, according to a link posted earlier, the initial flattop models had *very* thin material at the top under the rails (apparently enough to push a pencil through? would like to know more about this story).  Colt thickened the area which raised the rails. They chose to raise the front sight so existing rear iron sights would still zero.  Their plan worked perfectly until all the meddling kids came around and decided not to use the "F" FSB on flattops... And of course, I may be wrong, but that's how I understand it. So then, when Colt eventually started to use the now Mil-spec shorter flattop upper receivers they had to make up for the loss of the taller flat top by making the DCH sights taller so that they would work with the taller F FSBs? This sounds right to me, can anyone else confirm if this is right? I believe SNorman is speculating that Military/COLT changed the design of the original flattop to a flattop that has more meat in the rail area (made it thicker at the top)... A thicker top would cause the DCH to set higher... To compensate for the height difference, COLT then changed the height of the FSB to the taller "F" marked base...   The way I understand it, the milspec DCH never changed, it was the milspec FSB that was redesigned (made taller)...

What you're saying makes sense except for the fact that was pointed out in this thread that older flattop Colts where useing the shorter style DCHs. Also, I must know why Colt used the taller Mil-spec DCH in the first place?

Quoted: What you're saying makes sense except for the fact that was pointed out in this thread that older flattop Colts where useing the shorter style DCHs. Also, I must know why Colt used the taller Mil-spec DCH in the first place?

Correct, and it was a commercial version COLT that had the original shorter A2 FSB which needed the shorter DCH... The taller "F" FSB wasn't being used until the M4A1 was introduced with the flat-top with DCH... First was the A2 rifle then came the M4A1...  I figure there was/is allot of older A2 complete uppers floating around (warehouses, etc...) that were eventually upgraded to the modern flat-top receiver, which then would need the shorter DCH...  

Another thing to think about...

After the military would upgrade the A2 receiver to the flat-top, the rifle would be left with a short FSB and a DCH that had a RSB that was to tall... Do you realize whats involved in replacing a M16's FSB? It requires that you properly align and re-drill the new FSB to install the taper pins, and thats allot of work... It would be economical and allot easier to just leave the shorter FSB on the barrel and use a shorter DCH...

I sure hope I find out the answer to why there is a height difference real soon, before this drives me frickin nuts!

I have been an AR-15.com stealth observer over the last year.  There has been a lot of misinformation throughout this topic, which I felt I needed to chime in.

Shootersden you are correct there are two different heights of DCH’s Mil-spec COLT carry handle rear sight base (shelf) measures .833", the Bushmaster .791"... There is a .042" difference between the two.

So WHY did Colt do this?  This question was answered by Troy in a post about six months ago. Since, I am not a member I cannot archive a topic past 30 days.  If you find this post, which I think was titled “why do some FSB have an F marked on them” or something like that, this question will be answered.

THe F marked front sight base is NOT taller than a standard front sight base. They are both exactly the same height. What Colt did was mill the threaded flat for the sight post higher up in the front sight base, thus raising the mechanical zero of the front sight . Guess how much higher in the front sight base they milled the threaded flat? If you guessed.040, you are correct. If you have a standard FSB and an F marked FSB, compare them, and you will see that they are the same height, but the threaded flat in the F base is milled higher that the threaded flat in a standard base.

Quoted: Well, for skatyeighth time I will post that it AIN'T the flat top. It's the barrel length. Carbine type ARs almost always require a higher front sight point, whether thy're flat top or one piece uppers.  My SP1 carbine came from the factory in 1978 with a higher front sight. Rifles almost never do need the higher front point.Up until the advent of the M4 series, Colt used the same higher sight insert on carbines and submachine guns that Bushmaster now sells, for standard bases. When the Army didn't want to keep two different heights of front sight blades, Colt incepted the "F" series front sight base, in which the screw in shelf for the insert is the same .040 higher as the old type carbines had in the higher insert.  Colt and FN have now standardized on the "F" base for both rifles and carbines, because you can always screw the sight post diown further on the higher base in a rifle, but you can't raise it past a certain point on a carbine.So yes, if you have a carbine type AR you need a higher front sight point, flat top or one piece. Since you say that your sight base has an "F" stamped into the left side, you have the higher mounting point in the base and can use a standard sight insert.  If you have a rifle type with an "F" marked base, you would still use the standard sight blade, but will probably have to screw it down a few clicks into the base, which should be no problem.The old wives tale about Colt flat top/sight assys being higher started way back when the flat top was a new hot item, and some of the early aftermarket pieces did have non standard measurements. Those days are long gone. All the major makers now put out flat tops and sight assys within a few thounsanths of each other dimensionally. My Colt SP1 carbine, built years before anyone thought about the "F" base, needs a higher front sight point, accomplished by a higher post.  My Continental upper/Bushmaster sight assy M4gery needs the same higher front sight point, but since the Rock River barrel has a standard sight base, I also needed the Bushie higher post on it.

From the thread... "F" marked front sight base for Flattops?

Quoted: It was probably easier (read cheaper) to do the minor re-design of the FSB compared to doing a little re-designing of the DCH. WIZZO

Mill .040" less off the FSB or mill .040" more off the DCH.  Aside from the very slight difference in time spent on the milling machines it would take the same amount of work to do either one.

Quoted: I have been an AR-15.com stealth observer over the last year.  There has been a lot of misinformation throughout this topic, which I felt I needed to chime in. Shootersden you are correct there are two different heights of DCH’s Mil-spec COLT carry handle rear sight base (shelf) measures .833", the Bushmaster .791"... There is a .042" difference between the two. So WHY did Colt do this?  This question was answered by Troy in a post about six months ago. Since, I am not a member I cannot archive a topic past 30 days.  If you find this post, which I think was titled “why do some FSB have an F marked on them” or something like that, this question will be answered.

TowGunner, Thanks for the input, and glad to see this topic lured you into your first post...

Quoted: I have been an AR-15.com stealth observer over the last year.  There has been a lot of misinformation throughout this topic, which I felt I needed to chime in. Shootersden you are correct there are two different heights of DCH’s Mil-spec COLT carry handle rear sight base (shelf) measures .833", the Bushmaster .791"... There is a .042" difference between the two. So WHY did Colt do this?  This question was answered by Troy in a post about six months ago. Since, I am not a member I cannot archive a topic past 30 days.  If you find this post, which I think was titled “why do some FSB have an F marked on them” or something like that, this question will be answered.

I believe Troy said it was because Colt wanted to be different. That's what I remember from a post that was about two or three years ago, so I could be wrong and I probably am.  

Troy, said the FSB marked F and the non mil-spec are the same height, but the valley where the front sight post is screwed in is milled deeper on FSB marked F.  The reaon for this was because Colt did not want to stock two different front sight post heights in thier inventory.   They could contiune to use the same front sight post heights that were standard for the A2 20" This is what I remember Troy saying.

Quoted: Quoted: Well, for skatyeighth time I will post that it AIN'T the flat top. It's the barrel length. Carbine type ARs almost always require a higher front sight point, whether thy're flat top or one piece uppers.  My SP1 carbine came from the factory in 1978 with a higher front sight. Rifles almost never do need the higher front point.Up until the advent of the M4 series, Colt used the same higher sight insert on carbines and submachine guns that Bushmaster now sells, for standard bases. When the Army didn't want to keep two different heights of front sight blades, Colt incepted the "F" series front sight base, in which the screw in shelf for the insert is the same .040 higher as the old type carbines had in the higher insert.  Colt and FN have now standardized on the "F" base for both rifles and carbines, because you can always screw the sight post diown further on the higher base in a rifle, but you can't raise it past a certain point on a carbine.So yes, if you have a carbine type AR you need a higher front sight point, flat top or one piece. Since you say that your sight base has an "F" stamped into the left side, you have the higher mounting point in the base and can use a standard sight insert.  If you have a rifle type with an "F" marked base, you would still use the standard sight blade, but will probably have to screw it down a few clicks into the base, which should be no problem.The old wives tale about Colt flat top/sight assys being higher started way back when the flat top was a new hot item, and some of the early aftermarket pieces did have non standard measurements. Those days are long gone. All the major makers now put out flat tops and sight assys within a few thounsanths of each other dimensionally. My Colt SP1 carbine, built years before anyone thought about the "F" base, needs a higher front sight point, accomplished by a higher post.  My Continental upper/Bushmaster sight assy M4gery needs the same higher front sight point, but since the Rock River barrel has a standard sight base, I also needed the Bushie higher post on it.

I would like to believe this, but it doesn't make sense when there are so many Carbines out there that use the shorter sights and work just fine. Plus it doesn't explain why there are taller sights on the Mil-spec DCH. In fact he siad that even the carbines with fixed carry handles need the taller FSP and those fixed handles sights are .040 shorter than the Mil-spec DCH sights. So if what he says is true then there is no need for the taller Mil-spec DCH sights and only a need for the taller FSB shelf.

Quoted: Troy, said the FSB marked F and the non mil-spec are the same height, but the valley where the front sight post is screwed in is milled deeper on FSB marked F.  The reaon for this was because Colt did not want to stock two different front sight post heights in thier inventory.   They could contiune to use the same front sight post heights that were standard for the A2 20" This is what I remember Troy saying.

I think you mean the "F" FSB was milled higher or more shallow not deeper.

But this doesn't explain the need for the taller sights It only points out that they're there, unless carbines actually need the taller sights to work right. But then there's that pesky taller Mil-spec DCH.

Quoted: But this doesn't explain the need for the taller sights It only points out that they're there, unless carbines actually need the taller sights to work right. But then there's that pesky taller Mil-spec DCH.

And the fact that the flat-top 20" guns like the M16A4 have the taller FSB too, not just the carbines.  Colt uses a narrower front sight post on the carbines to account for it being closer, so since the part is different already there's no reason not to make it taller too instead of making the FSB higher and having two parts that are different.  Add to that the fact that non-Colt carbines like the BM use the standard FSB and FSP and zero fine with the lower DCH.  

And I don't see why a carbine would need a taller front sight in the first place.  The shorter sight radius would make each click slightly more MOA, so if the range of the regular 20" is sufficent the larger adjustment range of the shorter should be too.  If you figure in the lower velocity and argue that the barrel has to be "aimed up more" to get the zero point then the front sight would need to be lower, not higher.  

If Troy would chime in he would be able to put this topic to rest.  

Quoted: I sure hope I find out the answer to why there is a height difference real soon, before this drives me frickin nuts!

I think it's to late, we're already nuts!

Quoted: Quoted: But this doesn't explain the need for the taller sights It only points out that they're there, unless carbines actually need the taller sights to work right. But then there's that pesky taller Mil-spec DCH. And the fact that the flat-top 20" guns like the M16A4 have the taller FSB too, not just the carbines.  Colt uses a narrower front sight post on the carbines to account for it being closer, so since the part is different already there's no reason not to make it taller too instead of making the FSB higher and having two parts that are different.  Add to that the fact that non-Colt carbines like the BM use the standard FSB and FSP and zero fine with the lower DCH.   And I don't see why a carbine would need a taller front sight in the first place.  The shorter sight radius would make each click slightly more MOA, so if the range of the regular 20" is sufficent the larger adjustment range of the shorter should be too.  If you figure in the lower velocity and argue that the barrel has to be "aimed up more" to get the zero point then the front sight would need to be lower, not higher.

I didn't know that Colt uses narrower FSPs on their carbines. Is that something they do on their military carbines too?

Quoted: If Troy would chime in he would be able to put this topic to rest.

I think so too. gvidon212 should put in the title of this thread "Troy, Come help us!!!"

I didn't know that Colt uses narrower FSPs on their carbines. Is that something they do on their military carbines too?

I didn't know that until very recently when it came up in a thread similar to this one about sights.  Per that thread the standard A2 FSP is .072" wide, a .052" wide post would give the same apparent width on a CAR-length, but Colt thought that was too thin for durability and uses .062" on their carbines.  

By my calculations the .062" would give the same apparent width on a mid-length as the .072" on a 20".  As far as I can tell none of the other makers use narrower posts as nobody stocks more than one FSP.  My RRA mid-length came with the .072" post and I can see the difference in apparent width vs. a 20".  I'll probably order a .062" with my next Brownell's order, but I want to try the stock width with the larger XS apertures for a while first.

I'm not sure if the miltary M4s use the narrower post or not.  I think the other thread said they just use the A2 post to avoid confusion and having to stock two different parts.  I haven't verified that information, but I do know that SAW and Brownell's have different part numbers for "carbine" FSPs than regular AR FSPs.

Quoted: Troy, said the FSB marked F and the non mil-spec are the same height, but the valley where the front sight post is screwed in isnt milled as deeper on FSB marked F.  The reaon for this was because Colt did not want to stock two different front sight post heights in thier inventory.   They could contiune to use the same front sight post heights that were standard for the A2 20" This is what I remember Troy saying.

Fixed...  When compairing a "F" FSB to the standard one, the "F" FSB has the taller area between the ears...

On a Oly FSB and COLT "F" FSB (I don't have any others available to compare at this time), there is around exactly a .089" difference between the two in the milled area between the ears (the COLT "F" FSB being the taller of the two)...

Quoted: I didn't know that Colt uses narrower FSPs on their carbines. Is that something they do on their military carbines too? I didn't know that until very recently when it came up in a thread similar to this one about sights.  Per that thread the standard A2 FSP is .072" wide, a .052" wide post would give the same apparent width on a CAR-length, but Colt thought that was too thin for durability and uses .062" on their carbines.   By my calculations the .062" would give the same apparent width on a mid-length as the .072" on a 20".  As far as I can tell none of the other makers use narrower posts as nobody stocks more than one FSP.  My RRA mid-length came with the .072" post and I can see the difference in apparent width vs. a 20".  I'll probably order a .062" with my next Brownell's order, but I want to try the stock width with the larger XS apertures for a while first. I'm not sure if the miltary M4s use the narrower post or not.  I think the other thread said they just use the A2 post to avoid confusion and having to stock two different parts.  I haven't verified that information, but I do know that SAW and Brownell's have different part numbers for "carbine" FSPs than regular AR FSPs.

I come up with .0675" when measuring the width of my 1997 manufactured government profile M4 14.5" FSP to my 2004 SOCOM mid-weight 14.5" FSP...

Quoted: Quoted: If Troy would chime in he would be able to put this topic to rest.   I think so too. gvidon212 should put in the title of this thread "Troy, Come help us!!!"

OK, I did a search of the archives, and here is what I found in regards to Troy on why:

Quoted: I don't know why Colt chose to raise the sights .040" for their flattops,.................

archive.ar15.com/forums/topic.html?b=3&f=12&t=232021

Quoted: Troy, said the FSB marked F and the non mil-spec are the same height, but the valley where the front sight post is screwed in is milled deeper on FSB marked F.

That is a no brainer, you don't zero off the sight ears.  If you are going to make the FSB taller then the shelf the front sight post screws into has to be higher, hence why we refer to the F FSB base as being taller.

USGI M4/A1, M16A2, M16A4, and M16A3 weapons all use the same front sight post, that is part number 64507.

I don't know, but have heard that non US Property marked M4 Carbines use a thin front sight post.  Never paid attention to the front sight posts in my commercial Carbines in that I pull and sell the goofy barrels off those.

Ekie Can you please cut and paste Troys response on a new post.

Quoted: Ekie Can you please cut and paste Troys response on a new post.

As you know, im not Ekie but heres the post from Troy...

Quoted: Okay, there's a lot wrong in this paragraph (nothing personal). I don't know why Colt chose to raise the sights .040" for their flattops, but the rest of the story I understand well. The F-stamped FSB's aren't any higher than regular FSB's; the difference is that the channel where the post goes isn't machined as deep, putting the shelf .040" higher. This allows a standard-height post to be used, so that only one post size needs to be stocked. This is mostly a concern for the military, which buys only a few upper configurations and almost never rebarrels an upper with a barrel other than what was on it in the first place. All of the civilian manufacturers use the same sight base for everything. The reason? So that they can build any upper configuration without regard to the FSB height, and so that end-users can change their barrels/configurations as they please. For a civilian with only one or a few rifles, buying a taller post is far less expense and hassle than changing FSBs if he wants to move his barrels to different types of uppers. And it is indeed a problem to lower the post on an F-stamped FSB; the post won't go .040" down, so if you put such a barrel assembly on an A1 or A2 upper, you have to cut down your post yourself. The F-stamped FSBs may make sense for the military, who buys tens of thousands of rifles in the same configuration and rarely reconfigures existing rifles, but it's a poor solution for the civilian world. -Troy

Quoted: This is an 8 page circle jerk, not a bit of new info uncovered.

+ 1 on that... I only re-opened it to see just how far it had gone in 8 pages....