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

Not bad, but that trigger guard is fugly

Billet lower...

Billet lower, wrong pistol grip, wrong can, no buis?

The grip is fine. Can is close. No BUIS doesn't really matter. But that trigger guard on the billet lower kills me.

Shoot, fifty pages is like three days ago...






Yup, it's the LaserMax UNI-IR, I posted in your thread in the Lights & Lasers forum about yours as well.  

~Augee

There FDE, it's just a hipster filter

Valencia.

Lolskis.

Hipsters and their grey filters. Next thing you know you'll be wearing girl pants and eyeliner.

Yeah I'm waiting on a new lower to show up. It's the only SBR lower I have currently so works for now. It's an 80% I did

Can is temporary until my RC is approved

KAC sights are enroute and I'm not a fan of A2 grip so I'll stay magpul even if not correct

I've seen a bunch of MIAD's in use in pics, keep it if you like it. The CQBR I'm cloning now has an FDE MIAD on it too.

This poor guy is waiting for me to assemble it's final resting place...

Nice.

And excellent pic.

If you ever wondered if I currently hate you, you now have confirmation.

That thing looks brand spankin' new. Very nice.

Aww man, guess I gotta stop drinking craft beer and riding my fixie to work. Gotta lose the handle bar moostache as well....

Lol fixie. Never stop drinking craft beer.

Shitty pic, but this is what these damn guys have done to me over the last year.
3 SBR'd lowers  Sights, sights, and more sights, 4 prongs (one is a genuine) cans and cans on the way..........going broke fast, and lovin it.

Holy shit. 2 Elcans now? And I see an A1 made its way onto one of your CQBR's.

Whole lot of awesome in that pic my friend.

Haha I dig that BII upper on the A1 lower.

Went shooting a bunch this last week.  I found myself ditching the exps3-0/magnifier in favor of the su-230.

So far I like it.

Will likely build another cqbr upper and use exps on it.

Yeah, it was closer to 100 pages.  LOL.  Thank you for all of your help.  Great build!!!

The black RIS is my 300blk. Lower is my 607 and the "in the white" lower is engraved XM177E2. That one gets the old vinyl acetate stock when finished.
Two Elcans are probably temporary. I will eventually sell one of them, most likely the civie. Just scored the SU230 with Doctor.  I like the Elcan, but I'll say that the Eotech is much faster during drills........so I probably should put together another upper for it.  He wants motivation?.........I should post a pic of my PILE of retro parts, enough stuff to build 8 or 9, or 10 rifles/carbines if I ever quite hoarding parts and take the time to assemble them.

This makes me warm and tingling.....now I have to up my game considerably!  





Awesome rig, but you really need to paint that upper!!

WMX200 or Surefire equivalent?

REPOST!

PIC THREAD!

PEWPEWPEW!

Ok guys Ive got a couple questions regarding my block 1 CQBR build:

1. I think im going to go the CAR stock route for the lower. Is polymer acceptable?
2. Is pretty much any surefire light acceptable for a CQBR build?

Thanks for the info guys!

Also Pic thread. My PR m4 and the lower I will be using for the CQBR build. (Any help with anything I missed for the PR build would be helpful also)

1. Yes.

2. You'll be okay with most any SF light.

That PR needs some paint.

I know funny you say that I literally just came home from lowes with some camo rustoleum and some mesh netting......

also is anyone in here selling the qr stickers anymore?

In for QR stickers as well, I really need to up my poser clone status!

 
You can get an authentic one made to match your rifle for $104 for 1, or $107 for 2 etc etc.



Or for like $10 for a pack of airsoft ones that won't match your serial number.


 

Damn, that's a bargain.

I'm in for airsoft...that's more my speed!

So much CQBR win.

ma bitch

Everywhere.

That would be so much fun to do though. Lighting under NODs is cool too.

Got junk?     Somebody was looking for motivation?   I need to get motivated to assemble some of these.  Got a 203 project in there somewhere.

Their is a photo of a Magpul MIAD out in the field.

lol

well, at least the barrel is more or less the right length.....

Enlighten me.... Am i missing something.... Is this a new Iteration of the CQBR??? I really feel ignorant but the fact that it has gone a couple posts unaddressed is making me panic!!!   "rocks back and forth" Ohhhhhh hot water burn baby!! Hot water burn baby!!!!  

That made me actually lol.

I was just going to let him believe.


It's like a quarterly thing to post a super wrong version of a clone. There are a few who do it with the sole purpose to get a rise.

The bolt release might be spec too...

Yep, I was pretty much just ignoring it.

ECP, I suspect he may come back and brag about full auto, in which case have your pics ready for anal embludgeonment, CQBR interwebz style.

Sorry i had to bring it up then.... the train just went off the tracks for me when i scrolled down....

What's weird is they only come in flocks. It's almost never 1 for any span of time. Always in quarterly flocks of a fewish within a weekish or so.

clone thread trolling is a pastime for an immature few.  many have additional icons so that makes it okay in their eyes.

Next time just post one of your muskets.

This might be a dumb question, but can I use KAC 99051 front with a KAC 300m micro? Or is there even a non micro version of the KAC 300m?