Why Short Barrels Make Sense

Advances in weapons technology are bringing about a paradigm shift in the employment of long arms for Close Quarters Battle.  In the last 5 years, the popularity of subcarbines has grown exponentially.  The MP5 has been all but replaced by M4 Commandos and Naval Special Warfare’s CQB-R.  These small rifles offer greater power at short distance than a 9x19 submachine gun, as well as parts commonality and a familiar manual of arms with the larger M4 and M16A4.  They are only slightly longer than a submachine gun, but offer up to six times the effective range. There are, of course, a few disadvantages, such as functioning problems, muzzle blast and terminal effectiveness.  These problem have all been addressed, and today carbines are often quieter, more reliable, and just as terminally effective as their longer cousins.  As time goes by, technological advancements will continue to increase the popularity of the subcarbine, a term that is used to denote rifles of intermediate caliber that use very short barrels.

The advantages of the subcarbine are numerous.  Indoors, they are easier to maneuver with.  They do not “flag,” or give away an operators presence at a doorway or corner.  Also, they offer quicker handling.  They can be held at low ready where longer rifles must be brought to indoor ready.  When firing from the window of a passenger automobile, HMMVW or armored vehicle, they can be brought to bear more quickly, and stored more easily.  They also offer increased lethality and a greater effective range than a 9MM submachine gun.

The short barreled M16 is not a new development.  The first was the XM177, first used during the Vietnam War.  This peculiar carbine, one of the first of its type, featured a very short barrel, only 10 inches long.  It had A1 or “field” sights, and a two position collapsible stock, which was in later years developed into the multi position collapsible stocks that we use today.  To counter the obnoxious muzzle blast of this short barrel a small suppressor, called a moderator, was added to the end.  This brought the effective length of the barrel out to about 15 inches.  Many years after the original XM177 was introduced, we now have the M4 Commando from Colt the Heckler and Koch 416, the Noveske CQB, and a new 10.3 inch rifle made in house for the US Military.  All of these carbines feature A4 uppers with MIL-STD 1913 rails and 5 position stocks.  The 10.3 is built for Naval Special Warfare by the technicians at Crane, and called the CQB-R, or Mk 18.  It is built by modifying existing M4 carbines.

The 10 inch barrel has developed a reputation for unreliability among civilian shooters, one which is undeserved.  While Colt manufactured uppers have a reputation for reliability, some Tier 4 manufacturers use the wrong gas port diameter, causing severe unreliability.  This has been solved in the past by opening the gas port, or in some cases adding a suppressor of Krinkov flash hider, addressed below.  The new generation of subcarbines, such as those manufactured by Colt or Lewis Machine and Tool, as well as those M4’s modified by Crane, are generally quite reliable.  They do sometimes require an O-ring to increase extractor tension, and a heavier buffer, such as the H or H2 buffer.

Furthermore, Leitner Wise and Heckler and Koch have both introduced M4’s that use a short stroke piston instead of direct gas impingement, reducing fouling and smoothing the cycling of SBR’s.  Furthermore, both systems have been linked to an increase in velocity.  In the case of the HK 416, there are reports of 10.5 barrels equaling the velocity of the M4.  

One of the two primary issues that have forestalled the general acceptance of the short barreled M16 is the excessive muzzle blast caused by the use of a submachine gun length barrel with a rifle pressure round.  The introduction of electronic hearing protection from Wolf, Peltor and Sordin has allowed the use of these weapons in the environment which most suits them, indoors and in vehicles. Furthermore, suppressors such as Gemtech’s M4-02 and Surefire’s innovative new suppressor create a package only slightly longer than an M4 Carbine, and much quieter, while adding 40-50 feet per second due to a phenomenon called freebore boost.

The  most innovative solution to the p[roblem of excessive muzzle blast is known as the Krink brake, or KX3, available from John Noveske of JN Rifleworks.  This device was designed to mitigate the concussion of the 5.45x39 Krinkov, but works well on short M4’s as well.  The Krink redirects gas forward, making cycling more reliable and redirecting muzzle blast away from the shooter.  It does not reduce noise; it simply forces it away from the shooters ears, something that operators on teams can truly appreciate.  The tradeoff is an overall length that is roughly 1.25 inches longer than a similar barrel equipped with an A2 flash suppressor, and about 6 ounces more weight.

The second issue which has traditionally made the Commando unpopular is the 5.56 rounds dependence on velocity for lethality.  Tests on calibrated ballistic gelatin by Doctors Gary Roberts and Martin Fackler have indicated that general military issue 5.56 caliber bullets do not properly fragment below an impact velocity of 2700 feet per second, although they do exhibit partial fragmentation at velocities as low as 2500 feet per second.  The tissue damage caused by bullet fragments in the body is what causes exsanguination, or blood loss, the primary wounding mechanism of the 5.56.  While other tests have come to conclusions that are more favorable for short barreled 5.56 rifles, they have not been published and are not available for review.

The solution to this dilemma rests in ammunition that has only become available in the last few years.  MK 262 Mod 1 ammunition and the Hornady 75 grain TAP offer reliable fragmentation to a full 40 yards from a 10.5 inch barrel.  In comparison, the M4 Carbine with M855 fragments to approximately 65 yards.  Both of these numbers use conservative fragmentation threshold velocities.  Also in the works is a 62 grain rounds that functions in a similar fashion as the Russian 5.45x39.  Upon striking flesh, base of the bullet passes the hollow tip (not to be confused with Open Tip Match, or OTM).  This causes the bullet to yaw and tumble, increasing the amount of tissue that the bullet comes into direct contact with, greatly increasing damage at extended ranges and from short barreled rifles.

Overall, the advantages offered by sub-carbines outweigh the disadvantages, when they are used within certain parameters.  They serve a very valid purpose for shooters operating in close quarters or around vehicles, as well as civilian shooters whose effective range is limited by the legal necessity to show the need to use force.  As technology continues to improve, expect to see more sub-carbines in the hands of more shooters.

Taggage.

Quoted: Taggage.

ditto.  Nice article.

Quoted: The MP5 is still the SMG by which all others are judged, but since most users desire the SMG for its small size and light weight, it is being replaced by the M4 and M4 CQB-R, as well as the HK416, all firing full powered munitions. In some cases a suppressor is used to mediate the muzzle blast, although the supersonic crack is still present. The SIG is NOT better than the M4, only different. It simply weighs too much and can''t be easily adapted to use the same accessories as the M4. There was a time, not too long agao, when the Government was looking into its options regarding the 55X, but it appears that the HK416 has completely eclipsed the SIG. Cool beans. On the topic of the M14, it is once again in use because they are what the accountants call "sunk costs." They were bought and paid for before most of the men carrying them were born. They are exceedingly heavy, not as accurate as the M4, and the round they use doesn't come into its own until over 100M... not something we need when a long shot is 30M. The next DMR's will be 5.56MM. The M14 in sniper roles will eventually be replaced by the KAC MK 11's and SASS. The day of the battle rifle is closing. Indeed, all of the major battle rifles were rendered obsolete before they were designed. The future will belong to short weapons capable of being used in a police action. Long range will remain the terrain of the MG, and the sniper rifle, with the help of GPS and laser range finders. The rifle will continue to grow shorter, and more people will grouse, but the fact will remain that we need not ask a rifle, let alone the operator, to be prepared for a 500M shot on a torso when his war will be fought at 5M. To sum up my article: "We live in a 300M world." Pick your tools accordingly.

This is certainly in the spirit of my article.

Quoted: To counter the obnoxious muzzle blast of this short barrel a small suppressor, called a moderator, was added to the end.  This brought the effective length of the barrel out to about 16 inches, slightly longer than a standard M4 barrel with an A2 flash suppressor.

The moderator only adds 4" to the XM177 10.25" barrel.

Quoted: In the case of the HK 416, there are reports of 10.5 barrels equaling the velocity of the M4.

Until I see hard evidence of such magic performance, I will have to say it is impossible (based on expanding gas pressure, barrel friction, and barrel length formulas).

Other than that it was an interesting read, well done!

Quoted: Quoted: In the case of the HK 416, there are reports of 10.5 barrels equaling the velocity of the M4.   Until I see hard evidence of such magic performance, I will have to say it is impossible (based on expanding gas pressure, barrel friction, and barrel length formulas). Other than that it was an interesting read, well done!

+1 that sounds like the BS Arms Tech "gain twist" velocity claims.

If you want short, you can't really beat the P90. The only questionable thing would be the ammo's terminal effects on human targets out to 200m. It won't meet your requirement for 300m shots though, unless it's Stargate where SG1 can take out Goa'uld Death Gliders from the surface using the P90 .

I would have to say the 16" or 18" mid-length AR-15 is going to be a good compromise on both ends. It won't be that much more difficult in CQB. I've heard quite a few complaints about the lack of velocity from the 10.5" and 14" barrels. If you're that close that the 16" or 18" are cumbersome, might as well use a sidearm instead. And if the building is too hostile, call in the M1, M2, or M3 that is supporting you

Quoted: The new generation of subcarbines, such as those manufactured by Colt or Lewis Machine and Tool, as well as those M4’s modified by Crane, are generally quite reliable.  They do sometimes require an O-ring to increase extractor tension, and a heavier buffer, such as the H or H2 buffer.

I know there were some contractors from Iraq and Afghanistan who didn't agree with your assessment of the LMT shorties and they were running them over there. They apparently had quite a few reliability issues though I didn't follow the debate long enough to see how it sorted out.

Quoted: If you want short, you can't really beat the P90. The only questionable thing would be the ammo's terminal effects on human targets out to 200m. It won't meet your requirement for 300m shots though, unless it's Stargate where SG1 can take out Goa'uld Death Gliders from the surface using the P90 .

You mean you can't take out a Goa'uld Death Glider with a P90?

Damnit! That's what I bought one for!

Instead of modifiying existing weapons to work in a CQB enviorment why don't we just use weapons that dont compromise barrel length for overall length. The Steyr AUG or the FN F2000 are two excelent example's Or if you want use the British SA80 but that system has had it's problems. At what point does it make more sense to go to a new platform instead of modifing the existing one beyond recogonition with trade off's ? Shorter barrel = Shorter rifle but you lose velocity and effective range.  I'm a former AUG owner and it is a great system.  Quick change barrel's, Full length barrel in a small package, short stroke adjustable gas piston.  What more could you want. The A3 version has full length rails on it too.  I'm not too familar with the FN F2000 but I'm sure we will hear more about this as the civilian version is being rreleased.  I'm not cutting down on the AR, heck I own two of em,I'm just saying other tools might fit the job better.

Quoted: The M14 in sniper roles will eventually be replaced by the KAC MK 11's and SASS.

That would be a huge mistake IMHO.  No offense towards Knights Armament.  Reaching out to 600 @ 800 meters cries out Bolt Action to me.

And anything inside 300 meters, well as an Armchair Commando the Mk12 with Mk262 ammo looks like a winner.  

Quoted: Quoted: The M14 in sniper roles will eventually be replaced by the KAC MK 11's and SASS. That would be a huge mistake IMHO.  No offense towards Knights Armament.  Reaching out to 600 @ 800 meters cries out Bolt Action to me. And anything inside 300 meters, well as an Armchair Commando the Mk12 with Mk262 ammo looks like a winner.

While there is nothing wrong with bolt action sniper rifles, and the speed advantage of semiauto rifles is greatly reduced when precision fire is required, NRA Highpower shooters have proven beyond the shadow of a doubt that the AR10/AR15 system is quite capable of delivering rounds on target all the way to 1000 meters with the precision demanded by snipers.

I don't see a need to replace the M24 and the M40 with a more expensive rifle when the reasons for the replacement (greater ammo capacity and accessory rails) are an easy retrofit, but it is an undisputable fact that well built 308 caliber ARs give nothing up in accuracy.

Awesome first post!  This deserves a tack, IMO.

Quoted: Instead of modifiying existing weapons to work in a CQB enviorment why don't we just use weapons that dont compromise barrel length for overall length. The Steyr AUG or the FN F2000 are two excelent example's Or if you want use the British SA80 but that system has had it's problems. At what point does it make more sense to go to a new platform instead of modifing the existing one beyond recogonition with trade off's ? Shorter barrel = Shorter rifle but you lose velocity and effective range.  I'm a former AUG owner and it is a great system.  Quick change barrel's, Full length barrel in a small package, short stroke adjustable gas piston.  What more could you want. The A3 version has full length rails on it too.  I'm not too familar with the FN F2000 but I'm sure we will hear more about this as the civilian version is being rreleased.  I'm not cutting down on the AR, heck I own two of em,I'm just saying other tools might fit the job better.

Because bull pups aren’t all their cracked up to be I suppose.  If I had the need to go into a building and clear it again I’d happily take the faster mag change on an M16 over the quick change barrel option of the AUG any day.  If you really have the need to quickly change the length of your barrel do you have the time to sight it in?  Swap the upper on an M16 and the sights go with it.  Want to talk about shooting from the off shoulder around a corner?  

Wow.  ASU1911.  That's a fabulous first post.  If you keep this up, your going to put most of us to shame.  

to AR15.com.  





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Quoted: Quoted: Instead of modifiying existing weapons to work in a CQB enviorment why don't we just use weapons that dont compromise barrel length for overall length. The Steyr AUG or the FN F2000 are two excelent example's Or if you want use the British SA80 but that system has had it's problems. At what point does it make more sense to go to a new platform instead of modifing the existing one beyond recogonition with trade off's ? Shorter barrel = Shorter rifle but you lose velocity and effective range.  I'm a former AUG owner and it is a great system.  Quick change barrel's, Full length barrel in a small package, short stroke adjustable gas piston.  What more could you want. The A3 version has full length rails on it too.  I'm not too familar with the FN F2000 but I'm sure we will hear more about this as the civilian version is being rreleased.  I'm not cutting down on the AR, heck I own two of em,I'm just saying other tools might fit the job better. Because bull pups aren’t all their cracked up to be I suppose.  If I had the need to go into a building and clear it again I’d happily take the faster mag change on an M16 over the quick change barrel option of the AUG any day.  If you really have the need to quickly change the length of your barrel do you have the time to sight it in?  Swap the upper on an M16 and the sights go with it.  Want to talk about shooting from the off shoulder around a corner?

You make very good points!
For situations such as the one you mentioned, just take a P90. It's totally ambidextrous and the shells drop down. You can fire it from either shoulder, off the shoulder, like a pistol, up in the air, etc... The P90 balances right over your strong hand so you can shoot it one-handed if necessary. The only thing you may want is aftermarket optics like a PK-AS with the black/red dot.

The M16/M4 would be my choice for overall lethality, but since we were talking about compactness and CQB...

Great write-up.  

I would like to add that Wes at MSTN has introduced a very interesting and effective concept in the SBR arena (albeit, at the request of a PMC customer).  The idea equip an SBR with a DMR/SPR strength optic  and the supremely accurate but short length (approximately 10.5") Noveske barrels, capable of sub-MOA accuracy.  The end result is a handy carbine that is capable of hitting targets at long distances.

Pictures courtesy of Wes at MSTN:









If you're interested, I recommend you read the following discussion: www.tacticalforums.com/cgi-bin/tacticalubb/ultimatebb.cgi?ubb=get_topic;f=56;t=001171.

Justin

Quoted: Quoted: Quoted: Instead of modifiying existing weapons to work in a CQB enviorment why don't we just use weapons that dont compromise barrel length for overall length. The Steyr AUG or the FN F2000 are two excelent example's Or if you want use the British SA80 but that system has had it's problems. At what point does it make more sense to go to a new platform instead of modifing the existing one beyond recogonition with trade off's ? Shorter barrel = Shorter rifle but you lose velocity and effective range.  I'm a former AUG owner and it is a great system.  Quick change barrel's, Full length barrel in a small package, short stroke adjustable gas piston.  What more could you want. The A3 version has full length rails on it too.  I'm not too familar with the FN F2000 but I'm sure we will hear more about this as the civilian version is being rreleased.  I'm not cutting down on the AR, heck I own two of em,I'm just saying other tools might fit the job better. Because bull pups aren’t all their cracked up to be I suppose.  If I had the need to go into a building and clear it again I’d happily take the faster mag change on an M16 over the quick change barrel option of the AUG any day.  If you really have the need to quickly change the length of your barrel do you have the time to sight it in?  Swap the upper on an M16 and the sights go with it.  Want to talk about shooting from the off shoulder around a corner?   You make very good points! For situations such as the one you mentioned, just take a P90. It's totally ambidextrous and the shells drop down. You can fire it from either shoulder, off the shoulder, like a pistol, up in the air, etc... The P90 balances right over your strong hand so you can shoot it one-handed if necessary. The only thing you may want is aftermarket optics like a PK-AS with the black/red dot. The M16/M4 would be my choice for overall lethality, but since we were talking about compactness and CQB...

Metro,
No argument from me.  Although my entire experience with the design consists of ten minutes playing with a PS90 in a gun shop, I liked it!  I’d need to work with it for a while of course, but the ambi design and straight drop ejection were very clever and seemed to address two of the big concerns with the bull pup.  With 50 rounds at the ready, the mag change might not be as much as an issue either, although the brand new one I was playing with seemed a bit stiff and was kind of slow because of it.  Still, I suppose that works itself in with some use.  I’m not sure it should or could replace the Commando AR’s for general utility, but the true PDW concept definitely has merit and the P90 seems to be a step in the right direction.

My feeling is that unless you are willing to lug around two or three different rifles, one configured specifically for CQB, one for normal ranges, and one for long range, you are going to need to comprimise specilized ability for all-around versitility.  Just remember the old saying, something can be a jack of all trades but a master of none.

Quoted: Quoted: The M14 in sniper roles will eventually be replaced by the KAC MK 11's and SASS. That would be a huge mistake IMHO.  No offense towards Knights Armament.  Reaching out to 600 @ 800 meters cries out Bolt Action to me. And anything inside 300 meters, well as an Armchair Commando the Mk12 with Mk262 ammo looks like a winner.  hr

The reasoning behind this is to be able to make fast follow up shots, particularly when a sniper team is cut off and surrounded.  The average range at which a sniper shoots appears, by some reports, to be falling.  There is a lot of discussion about picking up .338 Lapua's to make up the difference over 1000M.

Quoted: Quoted: The new generation of subcarbines, such as those manufactured by Colt or Lewis Machine and Tool, as well as those M4’s modified by Crane, are generally quite reliable.  They do sometimes require an O-ring to increase extractor tension, and a heavier buffer, such as the H or H2 buffer. I know there were some contractors from Iraq and Afghanistan who didn't agree with your assessment of the LMT shorties and they were running them over there. They apparently had quite a few reliability issues though I didn't follow the debate long enough to see how it sorted out.

I have heard some good and bad, but most if it has been good, particularly if the rifles were bought from MSTN.  For instance, there was an operator who mentioned that the LMT's issued to SOF units were actually more reliable than their Colt M4's.

Seth

All spitzer type rounds tend to yaw when they strike material denser than air, there is no need to add an air pocket (which all FMJs have to an extent anyway).

Quoted: Quoted: To counter the obnoxious muzzle blast of this short barrel a small suppressor, called a moderator, was added to the end.  This brought the effective length of the barrel out to about 16 inches, slightly longer than a standard M4 barrel with an A2 flash suppressor.   The moderator only adds 4" to the XM177 10.25" barrel. Quoted: In the case of the HK 416, there are reports of 10.5 barrels equaling the velocity of the M4.   Until I see hard evidence of such magic performance, I will have to say it is impossible (based on expanding gas pressure, barrel friction, and barrel length formulas). Other than that it was an interesting read, well done!

Will edit the first comment.

The MV claims are made by a guy named Tim Lau.   he gets to see more 416's than I do, but I have not seen the testing.  Wes at MSTN has tested SS 12.5's to have the same MV as chrome lined 14.5, due to their chamber and polygonal rifling.  I have no hard numbers, therefore I left the statement particulalry weak, ie "there are reports."

I'm going to edit this now, please keep commenting.

Quoted: Seth All spitzer type rounds tend to yaw when they strike material denser than air, there is no need to add an air pocket (which all FMJs have to an extent anyway).

I understand that, but evidently the air pocket changes the characteristics enough that bullet designers find it a useful addition.  It does make the bullet as long as Green Tip, giving it the same weight, MV and BC, therefore the same dope.

I really question if it is all that useful a feature.  The round yaws just a little earlier, so you may get yawing in an extremity when you wouldn't with a M855.  However, the goal should be QC of the gilding material to ensure the round fragments.  The problems that is being run into is there are lots of ammo that don't fragment, hence are less lethal.

Quoted: I really question if it is all that useful a feature.  The round yaws just a little earlier, so you may get yawing in an extremity when you wouldn't with a M855.  However, the goal should be QC of the gilding material to ensure the round fragments.  The problems that is being run into is there are lots of ammo that don't fragment, hence are less lethal.

The match bullets used on the MK 262 and TAP loads have very thin jackets, and they fragement to a reasonable distance, if you consider the package that you deliver them in is submachinegun sized.  Using a lighter jacket would cause underpenetration with the longer barrels.  The VMax and other varmint bullets are a good example.  

The next best thing is to run a bullet that twists around and enters at high speed, over 2200 feet per second.  It may not fragment, but it won't make you any friends either.

Realistically, making solid hits in the Upper COM is probably the best any rifle is going to do.   It would be nice if they packed a little more lethality, but even the M193 that comes so highly reccomended fails to fragment approximately 20% of the time, due to inconsistencies in the bullet jacket.

Also, I would like to stress the line in the article about unreleased tests.  I can't tell you where, when, who or how, but some data came to my attention that vindicated barrels as short as 9.5 inches when used with Green Tip.

Along time ago I read the Ammo Oracle, and to a large extent I still agree with it, but I found myself being rebuked by operators when I asked them questions regarding fragmentation.  They don't feel that it is as necessary as the authors of the article claim.  They just shot until something worked.

Quoted: If you want short, you can't really beat the P90. The only questionable thing would be the ammo's terminal effects on human targets out to 200m. It won't meet your requirement for 300m shots though, unless it's Stargate where SG1 can take out Goa'uld Death Gliders from the surface using the P90 .

I think the P90 is an awesome concept, but the round's lethality is very much an open question.  

I've never been shot with a 5.7 round, and don't want to be, but I would much rather walk into a firefight my Colt SBR rifle and a 75 gr. TAP round than a 5.7 with potentially questionable balistics.

what about use of polygonal rifling?

I have been experimenting with this formula for the past four months. This involves mounting my S&B Short Dot scope to my 10.5”.  So far, it looks like a successful combination. The weapon itself is short, relatively light, and yet still capable of sub MOA accuracy when required. The S&B Short Dot scope provides excellent performance from contact to 300-400 yard ranges.




While custom barreled SBR DI AR's do have their advantages, they also have their disadvantages. Primarily, this involves more attention to set-up, PM, and dam near religious cleaning and lubrication. In my experience if the end user does his part they can be very reliable, and capable of sub MOA accuracy. My pictured LMT/ Noveske / LaRue / Schmidt & Bender Short Dot 10.5” has been ultra reliable. It has attended several relatively high-count classes with absolutely zero problems. I’m not particularly worried about the “Terminal Velocity” problems of 5.56mm SBR’s, shot placement means far more to me.

I do find the P90 suggestions to be very odd. While 5.7mm ammo certainly out performs 9mm ammo it cannot compare to 5.56mm at any range.

Quoted: I have heard some good and bad, but most if it has been good, particularly if the rifles were bought from MSTN.  For instance, there was an operator who mentioned that the LMT's issued to SOF units were actually more reliable than their Colt M4's.

Buying from MSTN is a whole different proposition than buying direct from Colt or LMT. MSTN is what? A one or two person shop with a well-justified reputation for quality.  MSTN could build me an upper with no barrel at all and as long as they vouched for it I would feel OK.

However, if you are talking about a large scale purchase (U.S. Army), then you aren't going to get that same level of quality in the build and marginal systems like the 10.5" are going to show greater reliability issues.

Quoted: I have been experimenting with this formula for the past four months. This involves mounting my S&B Short Dot scope to my 10.5”.  So far, it looks like a successful combination. The weapon itself is short, relatively light, and yet still capable of sub MOA accuracy when required. The S&B Short Dot scope provides excellent performance from contact to 300-400 yard ranges. img.photobucket.com/albums/v74/va_dinger/2005_1210LMTSBR0035.jpg While custom barreled SBR DI AR's do have their advantages, they also have their disadvantages. Primarily, this involves more attention to set-up, PM, and dam near religious cleaning and lubrication. In my experience if the end user does his part they can be very reliable, and capable of sub MOA accuracy. My pictured LMT/ Noveske / LaRue / Schmidt & Bender Short Dot 10.5” has been ultra reliable. It has attended several relatively high-count classes with absolutely zero problems. I’m not particularly worried about the “Terminal Velocity” problems of 5.56mm SBR’s, shot placement means far more to me. I do find the P90 suggestions to be very odd. While 5.7mm ammo certainly out performs 9mm ammo it cannot compare to 5.56mm at any range.

Just use a piston driven bolt system and that will alleviate some issues about cleaning.

As for the P90 suggestions, what is odd about it being used inside a building? Do you really need a 800m sub-MOA rifle for clearing rooms? With a flat trajectory out to 200m, 5.7x28 should work fine for room clearing.

Good article but the extra velocity, 10"=M4", is stupid- Take it out. LW already said this can't happen.

Great post and read. Thank you.

I've been debating weather to get the 14.5 or 16. I think I have my answer.

Quoted: I really question if it is all that useful a feature.  The round yaws just a little earlier, so you may get yawing in an extremity when you wouldn't with a M855.  However, the goal should be QC of the gilding material to ensure the round fragments.  The problems that is being run into is there are lots of ammo that don't fragment, hence are less lethal.

To compliment ASU1911s post I have some things to add. The reasoning behind the round (Hornady AMX) is to increase the lethality of issue ammunition without the cost and complexity of Mk 262. They want a bullet that is more lethal than M855 for the same cost. I do not know if the program is successful. I personally question the effectiveness of it as well, but someone has got to test it or its all conjecture.

Quoted: Good article but the extra velocity, 10"=M4", is stupid- Take it out. LW already said this can't happen.

It is what I have been told.  If you are talking about a Noveske barrel, particularly when he gets his chrome lined barrels out, it may seem more likely with the LW.  Furthermore, a suppressed 10.5 is about the same length as an M4 and has 40-50 fps of freebore boost.

So until I get numbers, it will stay in there as a reported event.  It references HK anyway.  I don't know what they did to get those results, and I certainly won't be getting the chance to try it anytime soon.

As to the LMT- I only go off reports.  The LMT's I have been around functioned well with preactice ammo, although one of the shorties blew primers with MK 262.  Their quality may have dropped slightly after they began civilian sales.

tag!

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Quoted: Quoted: Instead of modifiying existing weapons to work in a CQB enviorment why don't we just use weapons that dont compromise barrel length for overall length. The Steyr AUG or the FN F2000 are two excelent example's Or if you want use the British SA80 but that system has had it's problems. At what point does it make more sense to go to a new platform instead of modifing the existing one beyond recogonition with trade off's ? Shorter barrel = Shorter rifle but you lose velocity and effective range.  I'm a former AUG owner and it is a great system.  Quick change barrel's, Full length barrel in a small package, short stroke adjustable gas piston.  What more could you want. The A3 version has full length rails on it too.  I'm not too familar with the FN F2000 but I'm sure we will hear more about this as the civilian version is being rreleased.  I'm not cutting down on the AR, heck I own two of em,I'm just saying other tools might fit the job better. Because bull pups aren’t all their cracked up to be I suppose.  If I had the need to go into a building and clear it again I’d happily take the faster mag change on an M16 over the quick change barrel option of the AUG any day.  If you really have the need to quickly change the length of your barrel do you have the time to sight it in?  Swap the upper on an M16 and the sights go with it.  Want to talk about shooting from the off shoulder around a corner?

When i've switch between 20" and 16" barrels on my AUG the PoI stayed the same out to 100m (didnt have time to go to the 200m range).  Australian soldiers have commented that they can do mag changes with the AUG almost as fast as with an M4...of course thats the first/only rifle they trained with so there is no muscle memory to unlearn and retrain

Nice post.

Welcome to the board.

Hope you do well in your English Composition course.  Beware liberal professors are all around!!!

I think honestly the short barreled platform is by far the best but with limits on 5.56NATO being effective only in velocity thresholds then I see a change for the ammo itself. The Russian's designed the 5.45 with a hollow cavity at the tip inside the jacket, which adds to the unstability of the round upon impact, thus not velocity specific. There is no perfect weapon system, you trade range and lethality for weight. Overall the M16 design in a 16" platform is an excellent standard, 14.5" for most ops but limits on velocity and effectiveness for various ranges are due to the round itself.

Basically redesign the bullet itself- incorporate the Russian designed hollow cavity and a 14.5" barreled carbine will be sufficient for creating gross terminal wound cavities.

Quoted: Basically redesign the bullet itself- incorporate the Russian designed hollow cavity and a 14.5" barreled carbine will be sufficient for creating gross terminal wound cavities.

That is the projectile he was talking about. For civilians, LE and SoF, match bulletswould still be better though. Fragmentation beats yawing, but if the barrel is short enough and the jacket thick enough that it won't fragment anyway, might as well yaw.

SBR's fill a definite niche, but anyone advocating a full changeover is crazy. In my experience, 16" w/ a collapsiblae stock is plenty short for vehicular borne/roomclearing combat. The addition of 6.8 could be beneficial as it reaches farther and still fragments well. If I were setting up an armed force for general combat it would look something like this, 16" midlengths (or piston driven) chambered in 6.8, with some 20" barrels set up as DMR, and a few long range sniper setups (.308 or .300 WM), plus all of the various MG's, etc. I don't buy the shit about engagement ranges shrinking dramatically. The reports coming in right now are tainted because they come almost exclusively from urban scenarios. There are still plenty of reaons for a general issue weapon with a 200+ yd capability.

Quoted: SBR's fill a definite niche, but anyone advocating a full changeover is crazy. In my experience, 16" w/ a collapsiblae stock is plenty short for vehicular borne/roomclearing combat. The addition of 6.8 could be beneficial as it reaches farther and still fragments well. If I were setting up an armed force for general combat it would look something like this, 16" midlengths (or piston driven) chambered in 6.8, with some 20" barrels set up as DMR, and a few long range sniper setups (.308 or .300 WM), plus all of the various MG's, etc. I don't buy the shit about engagement ranges shrinking dramatically. The reports coming in right now are tainted because they come almost exclusively from urban scenarios. There are still plenty of reaons for a general issue weapon with a 200+ yd capability.

Yes but how about a 16" barreled system with 500 yd capability- hence my argument for redesign of the bullet itself to incorporate the Russian features that produce wound channels based on yaw. 6.8SPC is simply a crutch when the Russian 5.45 will do almost every bit the damage at 500 yds as 5.56 does at 200 yds, hence changing the bullet design of the 5.56 itself coupled with a heavier bullet say in the 70gr category would make the 5.56 a better round.

The current Military rounds already do damage due to yaw!!!

Any bullet that is rear heavy will yaw when it penetrates, fragmenting is just an added benifit of yaw.

Quoted: The current Military rounds already do damage due to yaw!!! Any bullet that is rear heavy will yaw when it penetrates, fragmenting is just an added benifit of yaw.

True but there main damage is caused by fragmentation, not yaw, which is velocity specific, hence most carbines are really effective only to a couple hundred yards unless adopting heavier weighted 77gr bullets and such or a longer barreled platform. The Russians designed a very small bullet that is very effective from a carbine length barrel out to 500 yrds- because they designed the bullet around yaw specifically with a hollow point in the tip. Basically they built a better bullet that is not velocity specific or needs fragmentation to be effective.    

A 5.45 bullet is not more effective from a terminal performance perspective than a 77 or 75 grain OTM that does not fagment.  Both bullets yaw at about the same depth and both are about an inch long and are a similar diameter. 5.45 is a horrible choice when 5.56 is available which gives you everything the 5.45 has plus fragmentation at closer ranges and a larger case capacity.

Lets be clear... 5.45 SUCKS and has ZERO advantages over current technolody 5.56 ammunition. NONE.

Quoted: A 5.45 bullet is not more effective from a terminal performance perspective than a 77 or 75 grain OTM that does not fagment.  Both bullets yaw at about the same depth and both are about an inch long and are a similar diameter. 5.45 is a horrible choice when 5.56 is available which gives you everything the 5.45 has plus fragmentation at closer ranges and a larger case capacity. Lets be clear... 5.45 SUCKS and has ZERO advantages over current technolody 5.56 ammunition. NONE.

Cost may be the primary consideration.

Quoted: Quoted: Quoted: Instead of modifiying existing weapons to work in a CQB enviorment why don't we just use weapons that dont compromise barrel length for overall length. The Steyr AUG or the FN F2000 are two excelent example's Or if you want use the British SA80 but that system has had it's problems. At what point does it make more sense to go to a new platform instead of modifing the existing one beyond recogonition with trade off's ? Shorter barrel = Shorter rifle but you lose velocity and effective range.  I'm a former AUG owner and it is a great system.  Quick change barrel's, Full length barrel in a small package, short stroke adjustable gas piston.  What more could you want. The A3 version has full length rails on it too.  I'm not too familar with the FN F2000 but I'm sure we will hear more about this as the civilian version is being rreleased.  I'm not cutting down on the AR, heck I own two of em,I'm just saying other tools might fit the job better. Because bull pups aren’t all their cracked up to be I suppose.  If I had the need to go into a building and clear it again I’d happily take the faster mag change on an M16 over the quick change barrel option of the AUG any day.  If you really have the need to quickly change the length of your barrel do you have the time to sight it in?  Swap the upper on an M16 and the sights go with it.  Want to talk about shooting from the off shoulder around a corner?   When i've switch between 20" and 16" barrels on my AUG the PoI stayed the same out to 100m (didnt have time to go to the 200m range).  Australian soldiers have commented that they can do mag changes with the AUG almost as fast as with an M4...of course thats the first/only rifle they trained with so there is no muscle memory to unlearn and retrain

Sorry, I didn’t mean to dis your AUG, I think it’s a great bull pup design and your barrel swapping/maintain zero experience certainly speaks to the quality of the gun.  However, bull pups as a class still leave something to be desired, IMO.  You’re not going to be swapping barrels out in the field anymore then I’ll be swapping uppers, since nobody’s going to lug around a spare “whatever” as they go about their job.  Since you’re going to be doing that back home anyway, then the quick change feature isn’t much of a selling point to me.  If I was going to swap a barrel and bet my life on it, I’d want to check zero every time, no matter what it did last time.  

Regarding mag changes, while head to head mag changes might be rare in a fight, the M16 is going to win every time, all else being equal.  Maintaining volume of fire is critical to overwhelming an enemy, even more so as the distances close.  How much is that second or two you lose with a slow mag change going to cost you when your opponent is in the next room?  Long enough to let him finish his mag change in the AK he’s using?  Finish pulling the pin on the hand grenade?  Second place pays in a horse race, if you bet right, but in a gun fight “almost as fast” equals “almost alive”.  

The inability to shoot from the off shoulder is a serious shortcoming anywhere, but particularly in the confined space of a vehicle or inside a house where corners abound.  I know most of these can be configured for left handed shooters, but making “lefty” take point every time you come to a right hand turn doesn’t seem quite fair.   The P90 address’s this, as does the FN F2000, so it can be overcome with the right design.   But the P90 does it by using a small cartridge that, as others have already said, is designed to compete with the 9mm, not the 5.56.  Whether the design can be scaled up for the larger cartridge is doubtful.  The FN 2000 deals with it by controlling the spent case, forcing it up a tube and out towards the front of the gun.  It seems to work, as long as the little gizmo controlling the empty case functions.  Think the M16 is overly sensitive to dust and dirt?  Only time will tell how the F 2000 handles it.  

There’s no denying that a bull pup offers a longer barrel in a shorter package, with all of the advantages that come with it, but not without cost.  

Quoted: A 5.45 bullet is not more effective from a terminal performance perspective than a 77 or 75 grain OTM that does not fagment.  Both bullets yaw at about the same depth and both are about an inch long and are a similar diameter. 5.45 is a horrible choice when 5.56 is available which gives you everything the 5.45 has plus fragmentation at closer ranges and a larger case capacity. Lets be clear... 5.45 SUCKS and has ZERO advantages over current technolody 5.56 ammunition. NONE.

Well let's see since clearly you have no idea what you are talking about. The 5.45 is within 75FPS muzzle velocity as the 5.56NATO. The 5.45 also has a steel core penetrator, but carries expansive wound capacity to ranges out to 500 yrds since it's basis of design is centered around yaw for wounding capacity. Now 5.56 has a slightly heavier bullet, also steel penetrator, but is limited to under 200 yards in most cases for terminal wound capacity from a carbine length barrel. Now both are 1.5" typical MOA rounds, very accurate- however the 5.45 has almost twice the range for terminal wound capacity than 5.56NATO and yet utilizes a lighter round. Not saying the 5.45 is superior but really 5.56 is a paper puncher past 200 yrds. The simple use of a hollow cavity in the tip of the 5.45 makes the round very unstable, sure it doesn't fragment like the 5.56 but terminal wounding capability in terms of range is twice that of 5.56NATO.

So why not design the 62 gr, 5.56NATO round, with a simple hollow cavity at the tip, that way it still retains the fragmentation quality in ranges under 200 yrds because of the thin jacket but also has that oh so nasty tumble superior yaw wounding capacity that the 5.45 possesses- basically the best of both worlds. We all know 5.56 does yaw, but no where near like 5.45, hell the 5.45 flips probably twenty times in less than six inches of balistics gellatin- just imagine it hitting a bone. Unstability, yaw capaility kills at greater ranges than gross fragmentation which is velocity specific.

Simple- utitlize the best of both worlds, create a better bullet, then no more SPR use, no more 77gr, no more 6.8SPC- since all of those being to fix the problems associated with a simple design flaw in the 5.56NATO.  

Quoted: Quoted: A 5.45 bullet is not more effective from a terminal performance perspective than a 77 or 75 grain OTM that does not fagment.  Both bullets yaw at about the same depth and both are about an inch long and are a similar diameter. 5.45 is a horrible choice when 5.56 is available which gives you everything the 5.45 has plus fragmentation at closer ranges and a larger case capacity. Lets be clear... 5.45 SUCKS and has ZERO advantages over current technolody 5.56 ammunition. NONE. Well let's see since clearly you have no idea what you are talking about. No dumbass it is you that is clueless The 5.45 is within 75FPS muzzle velocity as the 5.56NATO. The 5.45 also has a steel core penetrator, but carries expansive wound capacity to ranges out to 500 yrds since it's basis of design is centered around yaw for wounding capacity. And the 77/75 grain ammo has identical wounding properties at all ranges as the 5.45 only better terminal effectiveness at closer ranges. Now 5.56 has a slightly heavier bullet, also steel penetrator, but is limited to under 200 yards in most cases for terminal wound capacity from a carbine length barrel. Now both are 1.5" typical MOA rounds, very accurate- however the 5.45 has almost twice the range for terminal wound capacity than 5.56NATO and yet utilizes a lighter round. Not saying the 5.45 is superior but really 5.56 is a paper puncher past 200 yrds. The simple use of a hollow cavity in the tip of the 5.45 makes the round very unstable, sure it doesn't fragment like the 5.56 but terminal wounding capability in terms of range is twice that of 5.56NATO. Like I said current technology 5.56 ammo like the MK262 or 75 grain TAP has better accuracy than the 5.45 ammo and EQUL OR BETTER terminal effectiveness at ALL ranges from zero to 1000 yards. So why not design the 62 gr, 5.56NATO round, with a simple hollow cavity at the tip, that way it still retains the fragmentation quality in ranges under 200 yrds because of the thin jacket but also has that oh so nasty tumble superior yaw wounding capacity that the 5.45 possesses- basically the best of both worlds. We all know 5.56 does yaw, but no where near like 5.45, hell the 5.45 flips probably twenty times in less than six inches of balistics gellatin- just imagine it hitting a bone. Unstability, yaw capaility kills at greater ranges than gross fragmentation which is velocity specific. TWENTY TIMES IN 6" OF GELATIN!?!?! You are a troll, a retard or both!!! It has identical yaw characteristics to the 75 grain TAP you can buy right now.  Go read something and get some education on the subject and stop embarrasing yourself nimrod. Simple- utitlize the best of both worlds, create a better bullet, then no more SPR use, no more 77gr, no more 6.8SPC- since all of those being to fix the problems associated with a simple design flaw in the 5.56NATO.

Like I said the 5.45 round sucks for terminal effectiveness and has no advantage over 75 grain ammo at ANY range in soft tissue.  Go read a fucking book and come back when you get a clue.