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).

----------

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.

----------

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

----------

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

----------

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).

----------

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)

----------

Link to previous threads

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

Just wrap electrical tape around it for a pull tab

Curious about RIS II rails with the FSP cut out... Have these been seen in the wild?  Son of a bitches are impossible to find for sale... hacksaw and a Dremel?

Even if you find one, you're literally going to pay an arm and a leg for it. So yeah, dremel. Please use a black rail and spray it though, lol.

Negative ghost rider.  Its going to happen on a FDE rail.  I'll make sure to make a video of it.  

Respect, ill be attempting this once I get my mk18s going. I'm also ballsy enough to grind shit

Johnny, do you still have yours, or did you sell it?

Attached File

how many black Mil issue RISIIs are there in the wild?

Here is a black one if anyone is looking

https://www.skdtac.com/Daniel-Defense-M4A1-RIS-II-FSP-Rail-p/ddf.118.htm

None that I've seen. But it is literally the same rail just a diff color. So a little rattle can and nobody knows any better.

I believe what we're talking about here is mk18 length rails for use with front sight base. They are extremely rare. Some of us have taken M4a1 ris ii rails and cut them down to somewhat clone the shorter version.
 I have one that I cut down, with the intention of doing some tig welding/machining to closer to original configuration. It's sitting on the shelf, waiting for a day that I have nothing else to do.

Same here. I prefer the darker anodized versions as well.

Word I got was that most were sold to .mil even if we've never seen them. I made one from a cut down M4 RIS II FSP, but cut down doesn't do it justice. Stoner beveled the edges and even tapped a hole in the bottom to match the factory version. Attached File
Attached File

Sold it. Someone offered a super duper outrageous price for it, and I couldn't turn it down, lol.

How much?

About those BUIS on CloneDiseased rig, I dig it.  I actually like looking down sights that are a little bit higher than stock on an AR.  So that would be ideal if you ask me.

I don't recall that on Augee's though.  Huh.  Only set I recall is his CQBR with an eotech and an IR laser on the very front of his rail.  And nothing else.


And oh yea, it was in the bathtub.  

short on rail space?

Are you speaking of these?

There's a reason I switched to the EXPS

Got the new ST07 in so she's done.

Here's my block 1 again with the Peq 2 an el cheapo bump helmet, and my PVS7s.

Your rifle has chickenpocks

@cjwwd2

I’m extremely jealous.  Would you ever sell one?!

Only if I had found and purchased a Knight's MRE rail

Took the mk18 out for first time in a while. My girlfriend was easily hitting 300m steel with the EXPS3-0

I’d have a hard time not selling mine for that much either lol.

Attached File

LSO grip best grip.

Hey man - where did you get the pistol grip in the first pic?  I am trying to clone a SAS c8 cqb... thanks bud.

So, is anyone building new clones or is everyone just making existing ones more correct?  I want to get started on one but I hate that the ridiculously expensive upper from Brownells is the only reliable source for the rail

No pics, but I do have this video from Instagram to offer

https://youtu.be/Scsj5LHjK6Q

Just keep an eye on the EE for one. The first time I even looked for one in over a year, I found a complete Colt upper with RIS II on the EE and snagged it. Literally like 2 mins of searching.

Speaking of. I picked mine up from Brownells saturday. And only a month old.  Budgeted to one part a month until it's done.

Nice paint on that rifle!

It's an LSO grip, numrich is where I got it I think, don't know if they still have them. Attached File

Clear your inbox and PM me...

Thank you! Good ole rustoleum khaki and brown

Nice, I ordered one of those from brownells as well. Supposed to be delivered tomorrow. Might go to work on my day off to pick it up.

That is exactly what I am going for.  For the time being gave up finding an old Surefire FA 212 can.... but that rifle with and atpial IS my exact planned build. Thank you for the motivation!

roger that, done.

I might have pics of it somewhere with a car stock and PEQ15. I'll see if I can find them.

Imagine building a Mod 0 clone using one of these lowers:

Gross.

Is a cool little chunk of history to have tho. Damn Norinco

A1 lower, but yeah, made in the wrong country.

The guy's selling the rifle for $500 cad, so abiut $400

Couple things

Trying to get my picture to embed

I got to play with my SOCOM RC a little and take a few pics over the weekend. Came in safe and sound from AU with zero problems. As a side note, I'm pretty sure if someone had been filming me when I cracked the factory seal and opened it, that it would've put off a golden glow like the briefcase from Pulp Fiction :D.

Looks awesome brother

I think its about time for me to pick up a new grip again. Been running the Colt A2 grip exclusively for like 4 years now. Probably time to re-broaden my horizons.

Sooo close to breaking down and buying one before they're gone.

Thanks :D.

Yeah, I was running a Colt A2 with the finger shelf ground off for awhile, but the BCM Mod 0 has really grown on me. I find the angle a bit more comfortable, especially when shooting for extended periods, and I like the overall design - basically a modified A1 with a different angle.

Do it. Just give in.

Anyone use or see a Colt 10.3 factory barrel (with markings) in a heavy socom version?

The only socom uppers I’ve seen lately from colt available to the civilian market are the 14.5” uppers. And I haven’t seen those in a few months. But I think they are available..