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

Last time I really saw Vans was in middle/high school back when skateboarding was really popular. I'm old.

All of those have been seen "in the wild" so you're good to go from that aspect.

Lights have some leeway, but most lean towards 600 series of some sort due to availability of the correct versions.  X300 doesn't seem in the spirit IMO.
As mentioned, Raptors seen ITW but I think CD mentioned it was unit buy?
Black KAC - hey if it's a 99051 just paint it :).  But just say NO to a micro
T1, seen ITW also, see page 1 pics

- X300 is just fine and is definitely in the spirit IMO. It's actually a really nice companion to the sopmod stuff (low profile, same length as atpial, etc…) (pic below)
- Since charging handle is such an easily replaceable personal part, pretty much anything reasonably goes here. If you like the raptor, run it.
- When CD was working as armorer and posting info for us, he mentioned a few times that BUIS he's installing is whatever is in inventory. There was at least one time where he was putting black ones on. You're GTG.
- T1 isn't a SOPMOD optic but is pretty common in the "personal replacement" or "unit purchase" world especially since they're already in the system and have an NSN. I think Force Recon runs them with GDI mounts. Larue mount also seems to be common.

(X300)

All depends if you wanna build an as issued gun or a gun with a bunch of personal bought items on it. The only raptors seen we're donated to a national guard SF unit by AXTS or Rainier

Does the surefire muzzle brake break the mk18 correctness code?  

I keep seeing flash hiders here

Surefire SF4P is correct for BKII, most run SF3P instead since 4P can be hard to find and $$$.


Also the KAC FH's for NT4 use correct on Mod0/BKI as well so you will see a lot of them.  

I stand corrected on the X300 :)..  Just seemed to "modern" to me for some reason...

I heard the 4 prongs were less effective compared to the 3 prongs.. and the only reason the military uses them is because they had a contract for the 4 prongers for whatever reason.

Man.. I feel like if my mk18 isn't clone correct what's the point?  I'd almost rather have a 11.5

Right according to Surefire they say the 3-prong works just as well (or maybe slightly better) than the 4-prong, but they had to supply 4p's due to the requirements of the contract, yeah.

From Augee...
The "story" is that the four prong variant was designed and manufactured at the request of the military in conjunction with the SOCOM-RC suppressor for the SOPMOD program. 

Before the commercial release, Surefire redesigned the flash suppressor mount as a three-prong design, known as the SF3P, which is supposed to be slightly more efficient at eliminating flash, as well as having stronger tines. While the FH556RC was never released for commercial sales, because the military contract specifications were for the four pronged version, it is supposedly produced for military contracts only. Because of this, there are extremely few in civilian hands, though they show up from time to time. 

~Augee

If you're going to shoot suppressed all the time I would just buy a brake to use as a sacrificial baffle. Just don't take your suppressor off so we'll know

Got my grip stop today.

It's so damn hard trying to get good NV pictures that aren't blurry.

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Btw, it's is frozen cock stiff outside in the northeast. Damn.

KAC FH can be correct for a Block II as that is the only suppressor MARSOC is running.  Never heard why they didn't convert over.  I had to order some KAC FH for stock in Iraq as I only had the SF4Ps and needed to work on their guns.


CD

Tiny, thanks for the additional info on specifics of 231a's.  Point I was making is that OP would see the difference between an EXPS3-0 and an SU-231a via the etched "SU" markings and what is on commercial versions.....just as an SU-230 LOOKS like a commercial model except for the SU/operational instructions etched. (and yes......the reticle differences)

EDIT:   notice that 3 posts above shows the very rare su231-A     (hey Brodband.....did you send that 231A back for a refund, or do you still have it?

All of these have been "seen in the wild" but are not common. Plus, I don't think that we have ever seen more than 1 of these items on the same gun. The more you start to deviate from the SOPMOD accessories the further you get from a clone.

black rails and black sights can be easily made clone-correct with a quick shot of off-gassed propellant and lacquer-based color.  

I finally have a gun I can post in here that's actually cloney. I'm usually not a VFG fan but it helps with the handling dramatically and allows me to reach the dual switch easier, PEQ should be added shortly and I think this one is done.

That gun is awesome. Have you ever tried the Magpul AFG? That works really well for reaching the dual switch.

Edit: it also works well for keeping the cords secured. Here is a shot where you can see both sides where the cords run.
Attached File

I have a Gripstop on my other 10.3" and aesthetically I think it looks better but only works for me if I run the dual switch at the 12:00 (not going to work with a peq), I've never tried a AFG but thought it might have the same effect, might be worth checking it out because I do like that cord management

Specific clone. AFG related.

I've seen that picture and i'm going to ask you since its the first thing I thought of, do you not block the laser when actuating the dual switch with it in front of the LAM?

P.S. Badass rifle btw

Needs moar corncob.  I really thought about cloning that one too.  I keep getting sucked back into aimpoints for some reason.

ETA to answer above regarding the switch, you'd likely just block the illuminator and not the laser (if you're right handed)

I have a tan AFG I'll send you. It's the regular version and I don't like it as much as the AFG 2. Just PM me your address.

OK, Several pages back I have pics of my start to a CQB clone in pistol form, while I wait on my Form 1.  Now after constantly looking at this thread, it has got me spending more cashola.  Meaning, I had a great deal on a PSA premium 10.5 CHF upper that was the basis of it, now because of all this group think, I am going to pick up a 6920 OEM from my LGD and will be getting the upper cut down to 10.3.  Then I am going to use the colt lower to start my Mk12 build.  After that is done, I'll get another colt lower to SBR for my CQB, to make it more propper.
I've had a few 14.5's P/W at Adco, but never a barrel cut down.  Can I send them the KAC NT4 FH and have them time the threads so I dont need to use the shims?  Also, do they need to rework the port or do any mods other than the cutting and re-threading?   I wish this thread didnt exist...  I would have been happy with my pseudo clone with all the CQD, KAC, and other odds and ends.
Also, where do I get a Gen 1 Sopmod?

Awesome man, Thanks!

Yes you'll have to get port work when you chop the barrel and its free with the barrel cutting service from ADCO. Just specify you want a .070 (mk18 spec) when you send your barrel in. Not sure on timing the NT4 but honestly I'd just use the shims vs paying for extra work. Just look at the EE under lower parts, they pop up pretty often or put a WTB out. Going rate for a gen1 LMT is anywhere from 100-150

What is the correct stock for a Block II?  I see SOPMOD on the list, but is it Gen 1 or Gen 2?  I've seen multiple pictures with black and multiple with FDE, so I'm guessing color isn't too big a deal.

I freaking love looking at all the clone builds, but looking back at the real deal just puts a smile on my face I can't remove.  A couple of team guys used Hogue pistol grips on their rifles.

Hogue grip, electric tape and a f#$% you attitude. 

Attached File

has anyone ever ran a mk12 PRI fsb on a block 1 or mod 0 mk18? any pics of such maybe an arms room special? i have a 10.5 but i swapped the fsb for a PRI becuase its just so nice not to have a fsb under my red dot. 

You mean like this Micro?

Nice. I think I saw the ad you scored that from.

 Well done.

It's really common to see pics with guys having their rifle setup like this lately. I think there's some school out there teaching it.

And yes, presumably they're only using the white light button on the dual switch and when they need to use the laser they're using the fire button on the top of the laser, not the dual switch. The dual switch is just still used because it's either a)already what's around or b)an integrated picatinny mount vs. having to tape it on. Having it setup like this let's you get that extended C-clamp that's all the range right now for daytime shooting.

I feel like it would bother the hell out of me.

*side note* - does anyone have or know where I can get an empty insight box for the m3x? Have the light and both switches, my OCD is kicking and would like the plastic box as well. Thanks ahead.

Yeah, he still has it. I know this because he won't sell it to me, lol.

I technically need the even rarer XPS3-0 though. I'm starting to think those Tier Juan guys are trolling me.

Anyway, I think the 552 is going to be the placeholder for now.

(Also specific clone, just not very accurate yet, lol)

<img src="" />

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I'm currently trying to figure out how to get the screws off the bottom of the g33 mount. I got one out, but I stripped the shit out of the other one.

Edit: Nvm.

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A1- I love the paint. Jealous all around.

That looks great!

Work stick.

Are there any units using AMBI magazine releases on their MK18's for the Lefties?

This is bad ass.  Why not just use the tan XPS2-0?  Nice Wilcox riser/flip mount.  I use them on my Block II.  I had several tan ones earlier this year, but I ended up selling all of them.  I should have just kept one. =(

No, no. What you should have done, is kept three, and sold one to me and one to CloneD. ;)

And yeah, I guess I could use the xps2-0, but,....

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Is the xps2-0 not discontinued too, though?

I've got one you can have. Shoot me a PM and I'll mail you one this weekend.

The kids with money got the Vans.  I had Chuck Taylors.  Red...  But ollying tears the crap out of the outside of your front foot on chuck taylors.  I think Vans were double layered right there.  

Way off topic, but a cool subject.  I do have a friend that is even older than I am that has a pair of Grey Vans with white soles.  They looked nice.  

Did someone say what about a T-1?

...


CQBR needs to lower its carbon footprint

Rattle can sentinels > black

"Black KAC - hey if it's a 99051 just paint it :).  But just say NO to a micro"

Nope I was referring to KAC Micro Front sight :).

Whaaattt?  and you tell me this 7 months into waiting on a SOCOM lol  

Lefties will put them on their guns. I've seen a bunch.

We have some commonality.............I have some spray paint.