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

Haven't heard anything. I know a few guys were still waiting to get updates from the last run. Not sure if they had to pay in advance or not.

eta- I've got one more build I want to add to the collection. I just need a 10.3" upper and I will have the Mike Glover tribute finished. I’ll take an updated pic once it’s complete. Plus a couple of these have changed since taking this pic.

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Replaced the A2 for a TD, just prefer the feel over the a2 any day. Oh and "in the wild" clone-ish correct and all that jazz.

Nice to know.. one of the oldest grips I have.... now i can put it in rotation/swap it...

Just when I was happy with my some of my uppers/guns - I found this YouTube video… by some cat “Texas gun vault” about mk18’s. He used all colt/knights/lmt… I made my lower, I have no clue where the parts in my uppers came from. I give up.

I did order a fde surefire and one of their Mp5 cans today. I’m pretty excited about the Mp5 can, looks pretty cool.

Salty


Less salty

Nice

CD

Love the salty look.

After seeing the black suppressor on it I’m convinced I’ll never be happy with black RC2 I have in jail. I think I need to get the FDE one my local store has in stock, this thread has costed me so much money.

What is the light mount in the second pic?

Just get it cerakoted.

The Texas Gun Vault guy is super popular in this thread!

The QD mount that came with the older M952V lights.

I think when your clone game is spot on like his, it’s just natural ppl will talk.

They were both used. I don’t get hung up on fde everything, They just happen to be in stock. I’ll decide which to keep and flip one.

I'll take that dusty old elcan off your hands. BTW, your setup is badass.


Surefire m93 mount. Comes with the m952v and some of the other m900 series

One thing i never understand is people who spend 10s of thousands of dollars on hobbies, which means they have good disposable income but don't take care of things which i consider most important like oral hygiene.
Why can't he fix his teeth?
I don't know, maybe i take oral health and having a nice smile more seriously than having a clone build.

Ah, thanks.

I thought it looked older, but couldn't place it.

I've been wanting to check out their reduced angle grip. Their std grip angle is too steep for my girly wrists. Anyone I'm here try their reduced angle grip and have any feedback?

Kinda liking the Black and Tan look. Swapped out the m620 for an m600c on a larue mount. The different mount gives the light a little more reach.

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The mounts come with 3 mounting holes so that they work with the older millennium series lights as well as the newer 300/600 series light.

Nothing wrong with the reduced angle ones, I use BCM's mod 0 on a lot of my other rifles due to the reduced angle.  Btw, rifle looks good with the Black and Tan.

Black RC suppressors were issued on SOCOM CQBRs?

Only seen one photo of a possibly black socom. It was on a URGI and it could've been another trainer can or lighting.

I will sell my teeth for some clone parts. No questions

I would do a testicle but not my teeth.

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The first step in clone addiction recovery, is admitting you have an addiction.
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Hmm looks like a black trainer on the b1/mod0.
Sweet.

Off the Gram from Greyfoxg

Glad to see a DD MK18 in the wild...
I had one built for a while now as my main HD and just received its tax stamp (in 10 days..that was fast!!)...

MK18 inspired DD upper/KAC SR15 built for HD...


with my Colt MK18 Mod 1 clone(ish)....

I sent SF a mail asking if/when they plan do do another run. I'll update the thread if/when I hear back.

@Tyrant556
What's that thing over the head of the Modlite?
Also, is the Modlite a 18650 or 18350 body?

It's a Light Head protective shield. Bought a couple here to test (against the SF Warcomp CTN) and rattle canned
I'm using the 18650 body...

Where did you buy the protective shield (URL)?
How much was it?

I got 'em here at EE a while back...

Modlite offers them now also, here is their link..
https://modlite.com/collections/light-accessories/products/lightshield?variant=30097892835387

There's a used 4 prong in the EE. Not that crazy of a price. No affiliation.

Eta- mk18 way I'm the back
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Any of you guys use the SSA-E instead if the SSA in your CQBR Block ii ?
How do you like it?

(Not quite clone related) So, after reading about aac 51t issues of not wanting to lock on the last tooth, I decided to just try and twist it a little further. I didn't have to add too much force, and was able to get it to engage that last tooth, and now it locks up solid with no play at all.

eta- pic to stay on topic.
I can't remember, is the blue, or the yellow surefire the blank firing trainer? I thought blue was for simunitions, but he doesn't appear to be running those.

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Eta- I guess they are both for blanks. A while back there was one of the yellow ones for sale in the ee. Almost grabbed it just for the hell of it.

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@Tyrant556 nice score on the 4p.

@Dyzastr

I was waiting to grab one more...

Jumped on it when I saw your post above...Thanks Brother!

Looking forward to receive it soon...

No problem! A 4 prong in the hand is worth 2 on back order.

Prob not Our boys but still a neat pic Attached File

Looks like the boys up way north.
Pebble Colt Stock, Emag.
Not familiar with the laser/illuminator device. Sweet pic.

Eta: I kick myself for passing over an entire box of loose Emags.
Eta: Royal Marine Commando, UK

10" barrel, shaved bayo lug. Any clue what the thing on the rail at 6 o'clock is? Looks like it might be for mounting?

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Any of you guys use the SSA-E instead if the SSA in your CQBR Block ii ?
How do you like it?

A little too light for my taste, SSA seems just right.  Plus I remember reading CD said he was putting SSA's in most URG's.

SSA are in the system for Mk11/M110s.  Mk18/URGs get SSF.  Mk12s used to get either.  Just put in a SSF on a MK18-1 (10.3") this morning.

CD

NSW:

Good reading for those of you with Warcomps who shoot with a RC/RC2 who haven't been aware of this topic from almost a year ago.

https://pewscience.com/sound-signature-reviews-free/sss-6-52-surefire-556rc2-mk18-556

ETA: For the TL;DR crowd, if you shoot suppressed the majority of the time, ditch the Warcomp and get the FH (or brake).

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