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 agree.

To them it's probably another additional duty they got stuck with, such as the UPL NCO who handles hundreds of piss bottles monthly.

Let the jimmies rustle

LOL

Was a stupid easy job though and got you out of a lot of stupid details.

That's like 1 years worth of mortgage payments sitting right there.

Any of you Guys have an Insight Dual Pressure Pad you want to part with? I'm having a heck of a time finding one to power the ATPIAL-C and M3X... That's not brand new or brape prices.

     I'm not greedy.....so I'll just take the one w/o a TD.

 Seriously, nice litter!

Thanks! Just looking for a good deal on another PEQ-C and that one with no TDVG will be done.

Specs for all 4?  Factory 10.3's (colt/dd/western sport mil overruns)?  All opened to spec (0.70) if cut down?  

Very nice;  definitely motivation to work on some block 2's.

Far right barrel is Colt factory 10.3 from SAW.

The other three are Colt chopped government 14.5" to 10.3" with .07 ports. All the receivers are Colt, the BCGs are either Toolcraft or Colt. Three of the four have SF4Ps and the one without the VFG has an NT4 for my pending KAC.

Black SOCOMs?

Rejoice and buy the hell out of all the black ones. Jeff will be happy.

The real answer is buy whatever color you can get your hands on and then paint....

Might be the yellow BFAs painted black.  Not seeing exit holes in the tubes.  One guy is running a 14.5" Simunition barrel.  Looks like a training exercise at Bragg or MacKall.


CD

My first thought once I saw the sims barrel, too.

That makes more sense.

FML... Can these BFA's be had?

Hello everyone, long time lurker here love everyone's guns. I'm currently trying to build my own mk18 clone, or well as close as i can since it's a pistol (damn Illinois laws). I could use some help on a few parts. I looked at the chart  on the first page when it says others on the rear sight would a KAC 200-600m be good to go or do i need a different one? Another question is the grip. I'm not a huge fan of the A2 would a tango down like whats used on a block 2 be kosher?

      Thanks in advance guys.

Yes.

Here it is.

The exit holes are there, just hard to see in the pics. They appear to all have had tape over them at some point, though a couple of them the tape has been blown/torn off. Here's a better pic of the tape.

Also, All the BFAs I've seen have been full size SOCOM size while these are definitely mini cans.

This is 28th EOD if that helps explain the supply chain on them at all. (My point being besides the cans there's also non-SOPMOD EOTechs, non-SOPMOD lights and standard PEQ-15s vs SOPMOD LA-5s)



Also cool to see some CQD rears show up. Those have been rarer in pics these days.

If the KAC is listed on the front then it would be fine.

Grips are pretty much personal preference. A2s, Ergos, Magpul, TG, ect...have all been seen.

The KAC 200-600m is GTG. Most people choose not to run them because the range is a little outside the intended purpose of a Mk 18 / CQBR. The 300m with large aperture is sometimes considered a better "fit". But the 200-600m is clone-correct along with the more common Matech 200-600.

The A2 feels the best with gloves on. But it's also a fairly easy user-replaceable part which means it gets replaced a lot by end users and pretty much any grip is kosher. The tango down would be fine and has definitely been seen many times "in the wild".

Anyone interested- PBS documentary "Navy SEALs- Their Untold Story" on Netflix.

Some footage of 10.3" guns in use by SEALs and Polish GROM while securing oil derricks and other infrastructure just prior to the 2003 invasion of Iraq. Also just a generally good documentary.

Anybody have any pics of the CQBR Pelican kit with the foam cutout?

Thanks, may have to get a 300m sight. Grips are something I'm going to have to experiment with. This pistol is my new go to gun so I kind of want some storage in the grip but I do actually like the looks of the A2. Dang this kind clone thing is tough especially on my bank account haha.

Not CQBR but:



Most of the pelican CQBR Block IIs seem to just be in the case.

This was stateside so not really a deployment kit, but in a pelican.

TD grip is best grip.

Everyone has the Tango Down (vertical) grips, but nobody seems to use the CQD grips, just the sling mounts.
How come? Too heavy?

I'm starting to get the block 2 itch in my arse again. That didn't take near long enough.

Well... looks like I'm putting of night vision for a little bit longer... Just got a Surefire SOCOM RC  in FDE

sell ya mine...

Money? Me?

I'm so broke I have to barter for everything. Which is why I'm still in amazement I even have a PVS 14.

I'll buy the pvs14 off of you so can buy it. lol

This makes my head hurt.

As bad as I want to say "you dun fucked up" just for the sake of saying it, that's probably the best move to get stamps out of the way first incase 41P. NV ain't going anywhere.

Congrats man!  You made a good choice!  I'm glad I got mine.  Did you find one in your state or is it a F3?

Good job!

 

Hard to find, expensive, heavy. Not really seen in use much anymore. They also take up a lot of space on the rail, if I recall correctly. I had one years ago, it was nothing special.

 

Found it at a gun shop in Florida so it is on a form 3. They listed it on Gun Broker which is how I found it. Paid $96 more than you did, but I figured I may not have a shot at one again.

Yeah, that was my thought process... I want NV more, but I can get that whenever.

Now I have a RC and RC2 on the way... so this should be exciting.

Thank you sir, you da man... that website seems ominous tho...

Heh heh. Store name = utmost clone correct.

Dear Diary,

I sure wish I could find a Taupe NT4 on a F3 in TN...

Ain't gonna happen.

Thanks Cap'n..

And since I know you would know, I got hella' excited between the time I got a notification and looked to see what you said.  Thanks!

Might as well just duct tape a corn cob to your flash hider. Or better yet, give me your duals, then I'll find you a taupe NT4.