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

No kidding, I stopped using it altogether - I left my old stuff there, but have been using imgur with good results...

Minor changes to the BKII, swapped the cut down Socom to a Colt CQB 103"... I know it's only 4oz but it feels soooo much lighter lol...

Also trying out the dual switch - not sure that I really like it, since I only have the light, the extra wire just kinda gets in the way.  Plus it's not as simple and easy to use as the tapeswitch in the grip.  I just got tired of fussing with wires every time I wanted to take the grip off (to shoot off a bag, for instance).  I need to get one of those velcro deals or maybe just some zip ties for the wires I think... 

Yeah, looking that way.. oh well.  Upper is being parted out, I have relisted with everything broken apart.

This will fix the unused cable issue

Dooooo it

lol I'd love to have one, but it really servers no purpose (except looking baddass :) if you don't have NODS right?

First snow of 2017

Oh yeah it's a very expensive red laser with no NODs

Dang... that's rad. This wins the thread today.

So I'm now going to build a mk18 clone I believe but want to change just a couple of small things. First of all, I'd like to run a B5 sopmod instead of the gen1 since it's a bit cheaper, and it has qd cups, I like a qd sling better. Next goes for the cqd mounts. Are they necessary? Hk hooks are kinda annoying. And I'd like to run a larue carbine rail instead of the KAC or the RIS due to availability and sling mounts.

Other than that, planning on a 10.5" barrel with a, arms 41bl front and running bcm for most of the other parts! Sound like a solid mk18 clone?

Also for optic, how about a vcog? 1-6 like on the EOD Guns, just a tad different flavour!

You might catch a little flak for a gen 2 sopmod, but no one would really care. The rest of your parts are no bueno.

Yeah so basically you are building a 10.5 SBR and nothing remotely close to a MK18.

Breakaway! Danger, danger, danger!

WTF, over. Not a Mk18/CQBR clone at all...

Thats beautiful!!!

If you want to build an actual MK18 clone, you're not gonna get it cheap.

Is this a joke?

LOL NO

Hahahahahahaha!!!! Winning!

Attached File

Who wants to discuss gas port size

Has to be... I think we are getting punked. lol

Not my ad and don't know the seller... just thought someone here might want it.

DD MK18 Upper

As stated you won't get any flak on the stock, most Mk18 I ran across were already missing the sling mount.  The 10.5" bbl is acceptable as well and  a SF 3 prong.  All the other issues is what makes a Mk18.


CD

HERETIC!! BURN THE WITCH!

Haha.. Coffee has been spewed!!

And we're off.


10.5's for the cheap guys

I will admit, the urge to chop is growing stronger.

'bought the only way to to get a new RIS II these days unless running across one in EE by sheer chance - somebody grab it, pull the RIS II and flip the billboard upper and ginormous gas port barrel and the rest :).  Will probably come out ahead factoring in price of RIS II when you can find one.

You'll be fine, except for the sling mounts, rail, barrel, buis, bcm parts and the optic.  Other than that you're good to go

  

or just buy that upper, krylon it like a man, and run it.  

Let's get that gas port discussion going again lol...  

So, I've decided to be more "responsible" and practical by getting an EXPS3-0 instead of a SU230.  Figured I could do a lot with the extra $1,500 I'd save.  Could put some of it towards an ATPIAL and some NV in the future.

I just have a quick question.  Is there a difference between the EXPS3-0 that I can find on Opticsplanet and those which are issued to the military?  In other words, is there a clone correct version of the optic (such as the SU230), or is it universal?

The EXPS3-0 that you are looking at is the same as the issued version..........minus one detail.  It isn't going to have the laser etched SU number/wording on it......same as the SU-230 has laser etched wording that the commercial version Elcan doesn't

Are the etched optics available for civilian use like the SU230 is?  If so, what could I expect to pay?

I feel bad for some of these guys. They get excited reading through the clone threads and decide they want to jump in and totally miss the mark, and then we kick the shit out of them.

Cloning is something you either get, or you don't.

They aren't sold to civilians, but they are out there. They are extremely rare though it seems. I can think of maybe one or two people in this thread that own one.

Wow, okay.  Regular ol' EXPS3-0 it is then

Finding a SU-231 is tough nowadays. Finding a SU-231a is nearly impossible.

None of the MARSOC EXPSs I've seen in pics have the SU-231A markings.

WHO WANTS TO TALK GAS PORT SIZE???



I am observing for future builds....

If I remember correctly this isn't true. I think the 231 and 231a have a deeper water proof rating and go through different testing from EOTech. I also remember reading years back that 553s with 231 markings aren't real 231s, they're just 553s using a 231 baseplate. You can tell a real .mil 231 because it won't have any L3 or EOTech markings, just like the 231a.

And yes, as someone as rightly already pointed out, almost all pics of MARSOC using the series it's just a regular EXPS whereas ARMY pics are almost always 231as.

I have a black one but have never been able to snag a tan one

Someone sell me a tan one

Hey Mk18 crew!

Wanted to ask about the "correctness" of a couple items. I doubt my build will ever actually achieve perfect clone status, but I'm trying to keep it somewhat authentic. Asking about the below items, and how "close" they are to being correct or seen/used in the field.

X300 with or without pressure switch kit
AXTS raptor charging handle
Black KAC front sight
Aimpoint T1

Thanks for the help! Hopefully post some pics up soon.

Not sure on the others, but a few pages back there was a post of in-service MK18's with Raptor CH's.

Dirty Vans. Dolla Bill, and a CQBR.....suppressor not shown... its a work in progress

Niiiiiiiiiiiiiiiiiiiiiiice.  You can't be grinding them finger bumps off and still be clone correct.    Just teasing.  Very nice.  I've never seen brown Vans before.  In fact, I haven't seen too many people wearing Vans at all.

Haha they are the all weather leather Vans