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

They started the day saying they lost it, come to find out they never hooked the trailer up and they said oh well it will get here when ever it can. Now I'm sitting and looking at ebay and watching a SU-230 trying to convince myself that I don't need it. Its all beat up and everyone is blowing the price out of the water.

What state do you live in Milspec? Also, what color NT4 is correct for a Mod 0? Is it black for the Mod 0 and Taupe for the block 1? I really like those taupe ones.

Edit: New page.

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I'm getting the bottom one cut down to 14.5. Because reasons.

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Well I just bought a TR21 to kick off my Navy EOD rifle clone, if that's kosher to post here.

I'll be buying parts while I'm on assignment, and have everything waiting for me when I return.

You selling a 4P?

He lives in the Peoples Republik of Commifornia

What I learned a couple months ago is suppressors were rare on MK18s but often people confused the MK18 with Block I. Either of the black or tan are correct.

I have two Magpul M93 stocks, one FDE and one experimental black one that I've only held on to in case I wanted to build an EOD. I've always had a thing for the EOD's but, just never took the time to build one since I have a Mod 0. Is the CAS-V rail still in production or am I relegated to trying to find one second hand?

It's still in production. OOS at BCM, but available from VLTOR directly for $240 with the rail kit. ETA: $228 at PSA.

I also have always had a soft spot for the Navy EOD rifle.

This is the one I would like to approximate...



Except I would scooch that Accupoint back a bit lol.

Thanks for the info DBM..

Operation parts has the ex model as well for 228..

Are all of the mk18/cqbr's colt lowers or have we seen FN lowers as well?

Taupe.



Thanks Milspec!

FN has only supplied M16A2 and A4s AFAIK (I know they won the bid for the M4 in '13 but I don't think they've delivered rifles from that yet?), so I don't believe you would see a CQBR in use with an FN lower typically.

I could be wrong, and someone that knows better could have other info for you.

We have FN "M4A1"s in the USMC. Not sure if the lowers have been used with CQBR URGs though.

Ahhh, okay. I wasn't tracking.

There's a CQTR in there somewhere....

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I'm sorry, I will try to keep up, but what is CQTR?  Is that for C (close) QTR (quarter)?  If so, that's just not quite how I remember it...

No idea but he has been saying it for pages, I guess it's cute thing to do now? Call guns the wrong thing.

well the T is right next to the B on the keyboard soooo...

Close Quarter Troll Rifle

CQBR that isn't correct and is used to "troll" clone folks.

Milspec came up with it I think. I personally think it is hilarious. Plus, it technically isn't a "CQBR".

Well I'm not the clone police, but if that is the case, this thread is not for "CQTR".  There are plenty of other alternatives for SBR's and RIS II's, so...

Close Quarters Troll Receiver, for the CQBR's that aren't clone correct, ya bunch of Nancy boys.

Except for the mil issue CQBR pics in this thread, none of the rifles in this thread are real CQBRs, so...

USN MK18s

Is it possible to have a closed group on this site?  Like invitation only.  Just wondering...

There's a few already. Was part of one for a while. Lost its luster pretty quick though when it became obvious many of the members never made it out of high school.

Some of you seem familiar.......

You can always ask in the correct forum, which isn't this one.

Not sure exactly what I should say here, you know because some bitches like to snitch.

Just dont pop a mother joke

another 4P posted for sale on EE


CD

Going to be a good New Years with some clones.

Trying to find another PEQC though. That's the last piece for other upper I have.

Only one guy there knows how to hold their rifle and use a foregrip.

Because it takes, Diff'rent Strokes to move the world.
Yes it does.
It takes, Diff'rent Strokes to move the world.

Yup.. Last one allllllllllll the way to the right

Going with "Swapped 10" upper with M4 upper for $500, Alex"

Whats it called if you put a Mk12 upper on that lower?

Yea,
He must have jumped on Arfcom to see how its taught here..

LOL

Hahaha. Did you make that?

No, Chris Osman did on Instagram. Was pretty funny.

SPR?

Keep in mind that Navy VBSS teams are made up of regular ass dudes from the ship's company that can pass a slightly more advanced swim test and can shoot with a minor degree of proficiency.  Any one is eligible...radar operators (OS, FC), cooks (CS), engineers (EN, GSE), welders (HT), supply bitches (LS).  I just hope that people don't think that every time they see a photo like this, they're looking at some group of highly trained stone cold killers.  These guys are probably thinking about when the next port visit is so they can crush some Columbian or Thai women...not about how they're holding a clear and safe carbine during a training exercise they don't want to participate in.

My guess would be that whatever it was called before the upper swap would be what it is a called after the upper swap.

I agree with the assertion that these guys aren't stone cold killers, but  aren't you oversimplifying just a bit? Particularly in reference to the quals and training?

They have to at least attend and pass SRF-B, SRF-A and VBSS schools, no? That's the info I got from VBSS guys I talked to in Manama, so if that's not right, then my mistake.

That's more training than your average shooter that watches Dynamic Carbine a couple of times and calls it a day.

Yes.  I am.  There is a pipeline of three different schools with a progressing degree of difficulty to get on the team.  I was writing with a degree of sarcasm based on the joke of a team we had on my ship several years ago.  And from what I saw, many of the other ships were in a similar situation.  The Columbia and Thailand comment is real shit though.

Ah, I gotcha. For a second you had me thinking those VBSS guys were just talking up the training. They may very well have been doing that still.

Oh, no doubt. That and the part about participating in an exercise that you don't want to be in lol.

We used to do a lot of VBSS training for ship teams (also MEU, etc but that's another deal altogether) and you're not too far off.  They do have to pass the schools mentioned below (as you said), but for the most part, the guys on them weren't very interested.

Repurposed receivers for M4s.