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

Sunfabish no new mk18 pic!

Okay, what suppressor is on this thing?  Also, I finally have a 10.3” barrel...if I ever get the time to build the thing out I might actually be able to post a picture in this thread!

Surefire blank firing adapter. Same as the one to the left, but with more 100mph tape.

Dat banana BFA wid fancy duct tape

snapped a few pics before a much needed range session yesterday

Half assed paint strip for the win. Love how that SOPMOD is looking

This is my buddy. You want me to ask him if it was 10.3" or 10.5"?

There is only one answer, and we all already know.

I just found out about the “Tiny Crumb” patches. Looks like the version with the can is sold out. Any word on when there will be another run? Any chance of seeing them with B5 stock, EXPS, magnifier, and a Surefire can?

I had Adco chop my 6920 barrel to 10.3" and this is how it came out. Can the experts tell me if this appears to be in spec?

Attached File

Good to go ETA looks like yours might be .05" shorter or something than this issued bbl. But hey, who gives a sheeit. Long as its not that devil 10.5!

Can anyone point me in the direction of the best price on the tan M300C's? I see them for $269 everywhere but I seem to remember that a few people were getting them for closer to $200 at one point.

Looks right to me.

http://www.impactweaponscomponents.com/product/surefire-m300-mini-scout-500lum-tn/

Maybe Adco has gotten better about cutting 10.3" barrels the correct length then

Can I ask if you marked it? Or just asked them to do 10.3" I know mines suppose to be a 10.3, but the fact that I can't see much difference between it and a 10.5 bothers me a little. Only sometimes. It's colt, so I'm half way there I spose. Yours looks a lot closer than the one I posted a few pics back. I'm mainly curious in case I ever have them chop one. maybe I'll have em take .1 off my barrel

Thanks man.  I honestly intend to clean up the receivers and rail one day

I did not mark it, just asked them to cut it down to 10.3" MK18 spec.

Thanks

Noice! Kind of miss my 249F, except how unnecessarily long it was.

*PIIIIIIIINNNNGGGGRIIINGRINGRINGRING*

Right. Is it much longer than a 4p? I know it's a little narrower. When I got my 3p it seemed the same length.  The lack of shoulder I think adds to the illusion of being longer but I think they are pretty close.

From what I just checked the 3p is 2.67 and the 249f is 2.7. But that's miles here.

Nobody in the Block 1.5 thread has a crap fit about the slight differences in how you do the end of the barrel.   I mean c'mon....  You got 14.5" A2X FH's.  You got SBR's with a true 14.5" (probably not very many).  You got the double washers.  And like my M4gery barrel, you got the 14.7" with A2 pinned.  Then there is that, is there that little step before the FH at the end of the barrel.  Mine doesn't have it.  Oh well.  I don't think I'm planning on sending it back to ADCO just to have that little bit taken out.  But then again it's not even the right barrel overall.  It's a 1/9 SS HBar.    Oh, and that didn't even include the 16"ers.  Nobody gives anyone a tongue lashing for them.  So almost 2" and over here .2" is a huge issue.  

Now, do I think it's dumb if people want it to be as close as possible to the real thing.  Heck no.  I get it.  Attention to detail is just something people do.  That's cool.  But I mean, if I sent someone a 6920 barrel and told them to chop it to 10.3" to be a MK18 clone, and they sent it back and it was 10.5", I wouldn't even know the difference.  I mean sure, people can tell.   And I understand that claiming something is correct when it isn't, is just justifying.   But making a big deal out of it either way is just........  Over the top if you ask me.

My Colt A2 20" doesn't have a bayo lug.  But in some ways it's a lot closer than some peoples builds, even if they have a bayo lug.  I mean there are always going to be degrees.  And any clone is just that, a clone.  It's not the exact thing.  Most of you all are so far out of the park with your lowers, since it has no happy switch.  But nobody says boo about that.  And the guys that actually do have an FA lower aren't lording it over everyone else.  At least not that I've seen.

I feel like its an even longer difference than that but it could just be an illusion from how the bottom of Surefire muzzle devices are designed.

So I have a lead on a gently used SU-231 marked EOTech 553 in tan with a manufacture date of May, 2007. The asking price is $425 shipped and he says he obtained it off eBay about a year and half ago. Am I stupid for buying one that old? Or who cares, #clonecorrect?

Input please!

It's an illusion for sure. Just laid them side by side and it's no even visually noticeable. They both make a 14.5 pinned legal length. That's loooong.

Don't do it! So who did you say was sellin it.....?

I say say confirm its legitimacy as an eotech, and go for it!

If you have the money to spend on one hand I say go for it.
On another hand, you are kind of picky about new parts (nothing wrong with that) and i think you would prefer your EXPS as its lighter/smaller/newer. So it may just end up another bought it/sold it thing. But if you want to try it out I say go for it.

I prefer the 553 only for aesthetics over the EXPS and nostalgia. Same reason is rather get an NT4 than an RC

^^This guy knows me too well. I did have a tan 553 (unmarked) at one point and liked it. Not even sure why I sold it other than I think I just wanted to try the EXPS3-0 because 553s were no longer going to be supported - even though I guess EOTech is still helping guys out.

Snag it. $425 is a good price.

Good to know! I got it for $410 shipped . Thanks guys!

Guess its time to get your pistol slide milled for an EXPS 3

Attached File

Hot dang! That's...quite the setup.

Oh my dear God

Hot dawg

So I have a bad feeling I may have gotten duped on the optic...

Armslist ad

I just so happened to dig around the web and came across the exact same pictures of the optic listed in an older ARFcom EE listing from an unrelated seller - purchased by an unrelated buyer.

EE Listing

Same pics, same serial number, same manufacture date as the guy told me.

I immediately contacted my CC company and asked to stop the payment and/or cancel the card. However, they said it would be better to allow the charge to post and then dispute it. Otherwise, if they cancel the card, I will definitely be stuck with the charge out-of-pocket. Yet, everything I read about Venmo says they're absolved from any scams.

Ugh...

I did email the guy back right away and asked him to explain. All comms up to that point seemed very legit. He even referenced the EXPS3-0 he replaced the 553 with. But the reality is, he could just be posting these every once in a while and taking in $400-$450 and not even actually selling anything. Then creating a different ad with different pics and using a different email.

That really blows. I remember that EE post from November.  I hope it all gets worked out one way or another.

Dbm, when you get tired of that 551, I'll give it a good home

People still buy things off Armslist? It's one of the most well known sites for scamming. WHY? JUST WHY?

Armslist gives me the heebie jeebies, but with that said- maybe the seller is just lazy and is using photos that he also found on a Google search.

Best case- you're getting an optic that wasn't accurately represented by photos, which could still be a good deal depending on the condition and provenance (eg- Law Guns).

Worst case- he's taking the money and running.

Can anyone tell me what model Surefire this is?  I am looking for something for a mod 0 or mod 1 build.

Thanks to @krdt I now know that is a M952 (not to be mistaken with M952V)

The M952 is a Surefire M951 with tape switch, ARMS #17 mount, and the I.R. filter. (Essentially- as a kit its a M952, the light by itself standard is a M951)

Thanks! I bought it off the EE as that. Did some googling and it totally confused me. Thanks for clearing it up.

Anytime man

LOL, Heavy.  Same light I had in Iraq 2005 and training through 2010.  I only put it on for night ops.

Okay, so newb question here that I should have known like 5 years ago,...but what's the clone correct sling? I've been using this stupid Magpul thing since forever, and I wanna get rid of these stupid endplates and swap them for the CQD's.

Also, just put a new upper together. Colt As Fuck upper, so no more dumbass DD markings on the side. Also, poopy stock.

Attached File


Attached File


And I'm reverting back to the correct orientation for the CQD. I tried the reverse, but I don't think I like it.