When discussing the Mk 18 / CQBR program, we can divide the history and discussion in to two distinct categories: 1) The weapon system itself / upper receiver supplied and 2) the group of accessories deployed on said weapon systems (SOPMOD).

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Mk 18 Mod 0 / CQBR

The M4 carbine and M16 are not ideally suited for all missions, so it was proposed that the modularity of the M16 series would allow a user to replace the upper receiver of an existing weapon with one more suitable to the task. One of two proposed special mission receivers that were planned for inclusion into the SOPMOD Block II kit, the CQBR has taken off on its own. Like the proposed Special Purpose Receiver, the Close Quarters Battle Receiver has been more or less taken on by the Naval Surface Warfare Center, Crane Division (often referred to as NSWC-Crane or just "Crane") as its own project following the CQBR's removal from the SOPMOD program. Just as the Special Purpose Receiver morphed into the Special Purpose Rifle, and was type-classified as Mk 12 Mod 0/1, the complete CQBR-equipped carbine has been type-classified as the Mk 18 Mod 0.

The purpose of the CQBR remains to provide operators with a weapon of submachine gun size, but firing a rifle cartridge, for scenarios such as VIP protection, urban warfare, and other close quarters battle (CQB) situations. The CQBR is designed to provide improvement over previous AR-15/M16-type weapons in this category. The CQBR is usually issued as a complete weapon system, and not just an upper receiver. The CQBR was once only available to Naval Special Warfare units, but the Mk 18 Mod 0 has become general issue for Visit, Board, Search, and Seizure (VBSS) missions and, as of 2006, for NCIS agents deploying to active combat zones.[citation needed] The Mk 18 is also used by the Coast Guard's Tactical Law Enforcement Teams, Maritime Safety and Security Teams, and Maritime Security Response Team and the United States Navy's Explosive Ordnance Disposal (EOD) Operators.

Wikipedia has a good article with sources on the original CQBR/Mk 18 Mod 0 and its development.

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SOPMOD

The SOPMOD Program Management Office at NSWC Crane, IN, provides standardized, versatile weapons accessories to meet needs across SOF mission scenarios. These accessories increase operator survivability and lethality by enhanced weapon performance, target acquisition, signature suppression, and fire control.

The CQBR itself was originally part of the SOPMOD program as an accessory replacement upper receiver for the M4. However it was eventually separated out into its own project.

SOPMOD accessories for the M4/CQBR originally included things like the KAC RIS/RAS, SOPMOD stock, KAC M4QD suppressor, AN/PEQ-2 illuminator/laser, ECOS-N red dot, ACOG, etc

The SOPMOD program has gone through multiple minor and major evolutions throughout its lifetime. The most significant is commonly defined as "Block II" and included the introduction/replacement of accessories that met the updated needs of operators. The most visually significant "Block II" accessory is probably the replacement of the KAC rail/FSB with the  Daniel Defense RIS II free float rail with low-profile gas block. Other updates include things like the Surefire SOCOM sound suppressor, EOTech RDS (553/SU-231 & EXPS 3-0/SU-231a), LA-5/PEQ ATPIAL, etc

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Link to docs and photo albums

 Presentation on CQBR from Crane
 Operator's Manual for Mk 18 Mod 0
 SOPMOD Program Overview presentation from Crane
 Photo Album of Mk 18 Mod 0
 Photo Album of CQBR with SOPMOD Block II accessories

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Because of the long history of both the CQBR/Mk 18 and SOPMOD programs, it's common to find weapons with various mixed configurations in the field, all depending on what time and unit the weapon system belongs to. Below are a few examples with descriptions to illustrate this.


Example of a Mk 18 Mod 0 in as-issued configuration including: M16A1 surplus lower receiver, SOPMOD buttstock, KAC RIS, KAC M4QD flash hider, Aimpoint Comp M2 in Wilcox mount, LMT rear fixed sight, CQD rear sling plate.


NSW Operator CQBRs with original SOPMOD accessories including KAC M4QD sound suppressor and AN/PEQ-2 IR Illuminator/Laser.


Member of a Combat Camera team with a CQBR with KAC RAS and M4QD flash hider but with other updated accessories from the "Block II" SOPMOD kit including SU-231a (EOTech EXPS 3-0), EOTech G33 Magnifier, LA-5/PEQ ATPIAL, Insight WMX-200.


Good example of "early" CQBR with SOPMOD Block II accessories including SU-231 (EOTech 553) and SU-233 (Insight M3x weaponlight).


Example of a more "modern" CQBR with SOPMOD Block II accessories including the updated SU-231a (EOTech EXPS 3-0) and Insight WMX-200 weaponlight.


Many times certain configurations are common within certain branches/groups. Here a Marine Raider is seen with a CQBR with an AN/PEQ-16 (USMC issued vs. the LA-5/PEQ SOCOM issued ATPIAL) and KAC NT4 suppressor (vs. the current Surefire SOCOM suppressor).

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Building a clone

If you're interested in building a "clone" of a Mk 18 or CQBR equipped M4A1, here is a basic parts list to use as a guide and get you started. This list is not exhaustive and see the * note above regarding personalized accessories.

                       | Mk 18 Mod 0                      | M4A1 CQBR Block I                   | M4A1 CQBR Block II                                      
Lower Receiver         | Mil-spec forged A1               | Mil-spec forged A2                  | Mil-spec forged A2                                      
Stock                  | Gen 1 SOPMOD (Black)             | M4, CAR, SOPMOD, CTR & others       | M4, CAR, SOPMOD, CTR & others                            
Pistol Grip            | A1                               | A2, ERGO & others                   | A2, ERGO & others                                        
Rear Sling Plate       | CQD                              | CQD                                 | CQD                                                      
Upper Receiver         | Mil-spec forged M4 profile       | Mil-spec forged M4 profile          | Mil-spec forged M4 profile                              
Barrel                 | 10.3"                            | 10.3"                               | 10.3"                                                    
Rail                   | KAC RIS                          | KAC RAS                             | DD Mk18 RIS II (FDE)                                    
Rear BUIS              | LMT Fixed                        | LMT Fixed, MATECH, & others         | MATECH, KAC 300m, & others                              
Front Sight            | A2 FSB                           | A2 FSB                              | KAC 99051 BUIS (Taupe)                                  
Front Sling Attachment | FSB Sling Swivel                 | FSB Sling Swivel                    | CQD                                                      
Muzzle Device          | KAC M4QD                         | KAC M4QD                            | SureFire FH-556-RC                                      
Supressor              | None                             | KAC QDSS NT4                        | SureFire SOCOM556-RC (FDE)                              
LAM                    | None                             | PEQ-2                               | LA-5                                                    
Weaponlight            | SureFire M962                    | SureFire M952, M962                 | Insight M3X (Tan), Insight WMX200 (Bronze)              
Optic                  | Aimpoint Comp M2 in Wilcox Mount | Aimpoint Comp M2 in QRP Mount, ACOG | EOTech 553 (Tan), EOTech EXPS3-0 (Tan), ELCAN 1-4x (FDE)

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Link to previous threads

 Previous Mk 18 / CQBR Thread Part I
 Previous Mk 18 / CQBR Thread Part II

I've done this before and it does work. Aluminum HVAC tape works great too.

Edit: Old pic for top of page

Attached File

Not sure if you're still looking but just got an email from operation parts that they have them in stock. They show 12 in stock. Never bought from them but I see there an industry partner.

99051-Taupe

Thanks for the heads up!  Ordered a rear site from OP a few weeks ago and requested to be put on the notification list when the front sites came in but didn't receive an email.

I've ordered various items from OP in the past and they're GTG.

Yep there was a point in time where we all got our 99051's (and Mk12 thread all got their FF RAS') from operation parts. Good to go

So, installing that BRT .070 port insert has kinda motivated me to do a little more work to the NQR Mod 0. Specifically, to start fixing some of the "Not Quite Right" areas, lol. I've been putting it off, but obviously I have some changes to make in that department.

I managed to find another SBM4/APF tube combo on the EE, so for starters it's KAC broom handle time :D. Slightly tempted to try painting the SBM4, but it probably wouldn't work out very well and it'll just end up being replaced with a SOPMOD anyway.





The most obvious thing I need to address is switching the LT150 for a Wilcox, so that's getting ordered ASAP. Other planned changes include an SR07 for the M300 and possibly ditching the Gear Sector in favor of the stock mount - there is something about the way the M300 sits alongside the FSB I'm not sure I entirely like. I'm also thinking about swapping in my extra Gas Buster, but I've kinda been hanging on to that until I get to do some real testing of the Raptor-SD vs. GB when suppressed. I wouldn't want to run the FDE GB in this without painting it, so I'll likely hold off on that for now. Of course, the 10.5" barrel is an issue, but I've decided to keep it until it needs replacing, so that's not going anywhere in the short term.

Lastly, I'm going to go ahead and get an F1 sent off for this lower. I was going to wait until I had a Colt or 80% lower to F1, but I think I might just go ahead with what I have now - especially with the idiotic proposed legislation to raise the tax from $200 to $500 in the pipeline. It's not that I think it will pass necessarily - although with the current environment of hysteria you never know - it's just a good reason to go ahead now instead of waiting.

Speaking of Wilcox mounts, anyone know of a source for less than $112 shipped? I'm thinking about backordering one from Brownells while they are offering 7% cash back with AJ, but wanted to check if anyone knew of a better deal.

ETA: Nevermind on a source for a Wilcox mount, almost the moment I posted that I found one on the EE, lol. Came with an LMT BUIS that I don't need, but that's fine.

Not a bad day today. The mailbox was stuffed when I got home. Had a colt fiber lite (n1), colt complete bcg, bikini for my Acog, and DD ris barrel nut wrench. Just waitin on a new standard barrel nut wrench to arrive and I'll be in business with my mod1. I have an upper ready to go for my cutdown m4 ris, but I'm still in the market for a mk18 ris ii Fde. One offer I had fell through not too long ago and the last one I had my eye on, sold. If anyone is lookin to move one, msg me. I'll take anything, new, used, beat to hell (priced accordingly of course). Id kinda like to find a more used one since I plan to paint. I know if I get a newer one I'll end up getting 2, one kept natural Fde, and one to paint.

Nice. I definitely can see it better now. How do you like havin the aimpoint on an offset? Does it feel bulky at all? It also feels pretty natural to transition to offset back ups. The ta31-Ecos is what I have set up currently and with some practice it becomes fairly easy to transition between 4x and cqb, but it's not as natural as the pivot to offset imo.

That's not his. It's a different picture of the same rifle you posted earlier.

I'll see myself out.....

Got shipment notification for my FDE Elcan 1-4x 556 - Kerif custom ordered one for me with the old style battery  With used ones going for $1800-2000 I figured why not just spend a bit more and get a new one.  Had one before and gave it up, and have regretted it ever since.

^ noice. One day I hope to join the elcan ranks. For now, Acog, eo, and aimpoint will have to suffice.

Congrats on getting another one, your old one is being well loved and used I promise. Got it riding on my scar sbr now, about to hit the range when they open

mil or civ version?

Oooh, in for the answer. Would be nice to get hands on a new one in .mil specs because milspec

Because cloning.

very nice!

Dat plate doe. Get any comments in public yet?

Dedication

Haha, that's pretty awesome. I will honk if I see you ;p.

Thanks!

Not yet. Just received it in the mail Thurs. Was also considering...

NFA TAX
PRO 2A



Side note: attended the Luke Days 2018 at Luke AFB today. It was rad! Pics over in the Hometown > Arizona forum. But here are two pics just because you can never have too much Warthog...

Civ - couldn't get the Mil.  Well I guess I could get one used, but seems most avail to public are Mil rejects for one reason or another anyway.

Brrrrrrrrrrrt! Miss that sound!

Got all the parts but no light

Anyone else here order a m300 from IWC? Ordered on Wednesday, site says they ship in 24hrs

Low-Pro by AMS Machine.  That's the older style with 1 allen screw.  Newer versions have 2 rubber tipped allen screws.  I have a couple for sale.

Yeah, I ordered a light mount from them 2 weeks ago.  I called after 5 days of not shipping, and the guy told me they were running more like 4-7 days till shipping at that time. He seemed annoyed when I asked why the website stated in stock stuff would ship within 24 hours.

Love me some BBBRRRRRRTTTTT

Yep took almost 2 weeks to get mine from IWC...

I ordered my M300 from IWC Monday, 3/12. I emailed Wednesday, 3/14 asking a question and after answering the question, he added that the light would be shipping that afternoon. I didn't get a shipping notification until Fri. They're in CO and I'm in AZ. It's supposed to be here Tuesday. Not a big deal, but definitely not 24 hour turnaround.

However, Optics Planet takes the cake. I ordered my SR-07 remote and the corresponding tailcap Sunday, 3/11 and everything was in stock. However the items didn't ship until Thursday. Not only that, but they shipped one item USPS - scheduled to arrive Monday, 3/19, and the other FedEx - scheduled to arrive Wednesday, 3/21. Here's the best part: my father-in-law was visiting and wanted to buy two rifle scopes locally. I found them on Optics Planet for significantly cheaper and we used a 12% off coupon found here on ARFcom. We placed that order a few hours after my order on Sunday night and his scopes had shipped by Wednesday! I don't get it...

You don't have to look far to find issues with OpticsPlanet shipping and customer service. They're also compromise-minded sell-outs in the same category as Dick's. They were founded during the AWB and they still party like it's '04.

Old Reserve bird from Barksdale now DM out of Tucson. They still have F-16's at Luke, or all F-35's now?

We've seen lots of A-10 activity the two separate times we've gone to visit the Pima Air & Space Museum. I guess there's an A-10 squadron stationed out of the base down there. As far as our visit to Luke yesterday, I did not see any F-16s; only F-15s and F-35s on display and a demo of the F-35s, which was awesome.

I was at DM last year, but I haven't been to Luke since tech school in fall of 2004. Davis Monthan AFB has the most A-10's of any USAF base in the world.

Yep. A10C training is one of the base's key missions, and the A10 demo team used to be based out of DM before it was dissolved. I grew up with them always overhead. It's an awesome platform.

Shooting through a pipe with a brake.



a bit teeth chattering.

I could only imagine. I shot at an indoor range for the 2nd time in my life last weekend and someone was letting off something that lit up the whole range and rattled my guts.

10.3s without a can suck at the indoor range, even with a FH

Before I had a can, people would leave the stalls near me after half a mag

I went to a dealer shoot and took a test drive of a MCX in 9 with a can on it. Bergara was also there and someone was popping off one of their bolt guns which I image were 308. This particular range was only 8 lanes wide. The vast difference between the 2 was astounding.

I even test drove the Rattler in 300BO with a can and that was still quite a pop indoors.

Credit goes to DOGDRIVER for this.

Making ready for range day...
My buddy brought his MP5 clone and we put a can on it, get some! That was a blast.

Couple more of the winter camo I hadn't seen posted.

https://www.sealswcc.com/navy-seal-photos.html

Sorry if this is the wrong place to post, I have read around 800 pages of this thread over last years deployment and I know people get touchy about certain subjects that aren't 100% clone. So, since I don't have a strict clone I don't post much here. I am posting because I am trying to get an adjustable gas block for my Mk18 upper for my NT4 that is waiting on form 4. I was looking at the odin works but not sure if the hump for the set screw will fit under the rail. I would love a micromoa but as they are no longer made, I don't want to shell out $200 for some random guy's used one. I know a lot of you have the same rail, barrel, and suppressor and was wondering what you guys have tried, other than buying a whole new barrel to chop down for a smaller gas port. Unless anyone wants to let a govnah go for a decent price. Tiny, if this post is no good here, feel free to delete it. Sorry, I really do admire your guys' rifles, I am just not addicted enough(yet/thankfully) to form 1 a colt lower to replace my already sbr'd LMT, or swap out my ta31h for the correct reticle even though I have used an H on an issued m4 but not a cqbr. Thanks in advanced. Rifle in question so you can see it is somewhat close to a clone, but not 100% there. My rifle

Check out the Black River Tactical gas port insert. You just drill and tap your gas block and thread their insert in it. Could be kinda fiddly trying to get it sorted, but you would never be able to tell from looking at it

Damn.. well that sucks...

Guess I'll hurry up and wait.

Well, I finally have it. After a journey fraught with danger, hardship and unnecessary waiting... can you guys say: Gear Sector Slim Scout mount in FDE? :D! It only took about 3 months, a false start with a backordered regular GS mount and ordering from 3 different places, but it arrived Saturday. Gotta say, it's pretty snazzy.





Also, speaking of the BRT insert, I got to test mine out in the desert yesterday and was very pleased with the results. The old .080 port in my Noveske 10.5" was an annoying bitch and still not to my liking even with an H3 and Sprinco Red; I'm happy to report that now with the .070 insert, an H3 and standard carbine spring it shoots almost exactly like my .070 CQBR. I ran Wolf WPA 55gr, Wolf WPA 62gr HP and some 5.56 Hornady Black SBR 75gr all with zero issues. The felt recoil and ejection pattern was almost an exact mirror of my DD 10.3 .070, so I'd say mission accomplished :D.

I like it!  It would be hard to part with my off-colored coyote brown one, though

I am all over that insert!  We are moving, so I have to wait until I set up the gun room in the new house

When is your Form 1 coming for that lower!?!?  I keep watching for you to put a Sopmod on that bitch!

Almost tempted to throw my Colt N1 on it... probably will initially just for the sake of technicality - that's actually the OAL I used on the F1. Not to say I don't have a SOPMOD ready to go as well :D.

And, unfortunately, that won't be happening for a few more months. The SOCOM RC should be around April/May, the F1 on the lower should be around July assuming the average 6 month wait times on individual approvals holds. The check was cashed 01/17/18 on the F1. Maybe I will luck out and be one of those guys that gets a 4 month approval, but I doubt it :\.

Right on.  Don't sweat that OAL stuff, run what ya brung.

I like the N1, though.  Works great with a C7 or irons.

Fingers crossed, you may be lucky!  I think I still hold the record for the longest F1 wait time in the MK18 thread

Hey guys, so I remember seeing in this thread where to get the UID stickers, but for the life of me, I can't find that post again.

Got any leads?  I just finally got a mk18 upper and I'm collecting stuff while I wait for it to arrive.

Thanks!

https://www.ar15.com/forums/ar-15/UID-stickers/118-713653/

ETA: Here's the guy selling them: https://carolinalaserworks.ecwid.com/