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

Alright, that confirms it.  DD MK18 it is.  That's the one I was leaning towards

Thanks

Colt, dd, andro all make 10.3". Colt being the obvious route for .mil correctness and all with some FN and colt/ diemaco sprinkled in. There are factory colt 10.3", or you can go the adco chopped route. DD works as do others, but, you know.

I remember when members would get called elitists or a snobs for saying colt is the way to go. Colt flakes I believe was the coin termed. hasnt happened in a long time but I remember laughing to myself while reading all the colt non colt arguments from a few years back. It was pretty entertaining.
Pic thread-
im not even sure if the top one belongs. It's almost a block2 mod1 eod if that were a thing.

I dont get twisted up over small shit like "omg using X mount instead of X mount" because end users switched shit as soon as they got it most of them time but when people use some 13.7" noveske or something and call it a mk18 because it's technically a sbr...just stop.

I have a lpvo on my mk18 upper

I picked up an FDE Grip Stop to try out on the CQBR... and an SBA3 :\.

Probably silly considering my F1 is way overdue and could be approved any day, but oh well. Grip Stop arrived today and the SBA3 should be here tomorrow. Not sure the Grip Stop will replace my beloved TD Stubbies, but I figured I'd give it a try. I've only messed with it for a few minutes so far and I'm kinda on the fence. We shall see. At the very least I'll probably run it with the SBA3 until my F1 finally comes back.

Whats market price for RIS II FDE used? Not seeing much in the used market for rails.

Gripstop is probably the only thing I haven't tried lol. For some reason the full size tango down grip work's for me so much better in the angled hand grip position but I'd be curious to try one of those sometime.

I just didn't want to start an entire new thread for that basic question.  This one seemed most appropriate.

I bought the DD MK18 upper off Brownells for $657 shipped after discount.  Gonna be my first AR.

Been wanting to get a gripstop myself but idk, kac broomhandle been good to me over the years. Plus I been lazy to order one lol...

if it don't work out for you lemme know if you wanna offload it.

I like where this is headed!

That is damn sleek. Dibs for when the stamp comes in. I almost got one but used prices were so close to knew with a discount code that I passed.

Eta- at least wth the sba3 you'll be half way there when the stamp rolls in. Hell, you could even find a colt 4 pos to run with the brace. Unless that's considered modification to the original design? Dum dum dum
I've switched through em all too, except for the Lanco/ b5grip stop, and always come back to the versatility of a full size td vfg.
That's ominous.

Attached File

Gawd dern, lookin better and better. Which riser?

It's a Knight short riser, took me forever to track the thing down.

Oh, I've got that department covered ;p. Got two Colt 4 position tubes on standby. And, once the F1 on the CQBR comes back, I can decide between LMT Gen 1, B5 poopy Gen 1, and a Colt N1 for good measure. I will say that having such a long wait has me well prepared, lol.

Starting to wish I'd bought another LMT Gen 1 when I had the chance, though. Ah, well.

I'll definitely let you guys know if I decide to get rid of the Grip Stop.

Please do post images to compare an SBM4 to the A3! I cannot make up my damn mind about which one I'd prefer but I may jump on the Brownells 10% train tonight just to get the order on file for now, on an A3 that is. I just cannot decide on the looks....I think

Otherwise, is it common to see a teardrop FA on a block II MK18?

Yeah, I'm pretty curious to see how the two compare. Other than the lack of adjustability and being slightly on the heavy side, I am very happy with the SBM4. Suppose we'll see.

Teardrops aren't super common, but they're out there.

FYI Botach has B5 sopmods in coyote and OD green for $49 shipped.

I don’t know what the top one is called, I just know the sound it makes when it oper8s.

Thank You! Was needing one for my URGI build.

CCT guy I was with in AFG had a BkII Mk18 with a teardrop.  First tear drop I had seen on a modern AR in the military not counting training when we had racks of M16 and M16A1s in 2003.

Ah ok. Yeah for a block ii, I know it isn't 100% correct but I do like the look.

I'm with you there, the SBM4 hasn't done me any wrong and it's got a decent look. But I'm very curious to see how an A3 leans up the back end let alone the ability to bottom out the brace to the end plate. But then that brings into play the whole ATF approved and 26" legal length deal.

Side note, what steel pills do you use? I'm weighing the option of switching to steel given it is cheaper and all. The downside is...not made in the USA. What say you?

When it comes to steel, Wolf is pretty much the only brand I buy. I shoot quite a bit of it and have no complaints - I've got 6,000rds or so of Wolf through my CQBR without malfunctions. So, it's reliable and more than accurate enough for shooting drills and bulk practice. It compares very favorably with the accuracy of most bulk M193/M855. When I can get Wolf Gold at $240-$250 delivered, I shoot that... but it's not consistently that cheap.

Keep in mind that shooting bi-metal projectiles is invariably going to lead to faster barrel wear; that's pretty much unavoidable. However, even taking faster barrel wear into consideration, the cost savings compared to shooting brass more than offsets the cost of early barrel replacement. Say, for example, you need to replace a barrel at 10,000 rounds due to shooting steel: after 10 cases you've saved at least $500, and probably more like $750 to $1000 over the cost of brass. Even swapping in a quality barrel, you're still several hundred ahead.

So, to me, shooting steel makes a lot of sense; cheaper ammo/more practice :D.

...So since you guys don't have select fire lowers, heres my interpretation of mod -1 block4...its built on an aero upper with a 11.5" barrel, oh and a Troy alpha rail cause the rails hurt my hands. I looked back and I guess I started following in 2013. Before the first big thread change. I went off the date of the current thread, but forgot it started up a few different times.

hey, how much is a like new in box Fde or black docter worth these days? They've been poppin up and I want to get one but I'm not sure where to start price wise. Thanks.

Ping!

Eta - great snag on the aimpoint combo. Got my eyes on one too.

I feel you. I build my rig anyway so I have no issues swapping barrels when the time comes. Hell, that's practically an achievement anyway....to reach a certain benchmark of rounds and need a critical part replaced. I might try a case of the Wolf Military Classic. You get your stuff from SG? And hey where are those A3 photos?!

My man!  Just got me 2!

I thought it was a great deal. I already have an aimpoint 3x mag setup but never hurts to have another.

I get most of mine from Brownells - when they have it. Ends up being about $20-$30 cheaper per case than SG. FYI, Wolf WPA and Military Classic are both the same, so go for whichever is cheaper.

Actually about to install the SBA3 right now :D.

Well, I guess I got approved because Somehow my picture is magically up on my post. :)

So its the MCX based suppressed URG going to be the actual new block 3 (something), or just some other "available" URG?

How you feel about the Barnaul laquered stuff? Same same or different?

i wouldnt doubt the MCX getting some contracts with the way sig has been lining peoples pockets to win has been "winning" contracts recently.

They did, that's why I'm curious .  Kind of ugly as hell, but then I actually like quad rails.

quad rails are still the king when it comes to looks imo.

mk18 and mk12 are easily the best 2 looking in recent times.

No experience with it, but Barnaul is who makes WPA/Military Classic for Wolf; I'd imagine it's GTG assuming that other than the lacquer it's made to the same specs as Wolf. One of the reasons I prefer Wolf is that it's loaded hotter compared to other steel brands. That, and the quality is very consistent (at least in recent years).

Anyway, about to take some pics of the SBA3 now.

Not 1st hand, but I've heard the liqueur can gum up a chamber. Any truth to that?

Dont remember who it was but someone recently did a video on that.

The lacquer wasn't a problem at all but the steel not expanding and causing gas blowing back into the chamber caused a few problems.

Mostly gum up around the bolt face, extractor, and barrel extension. I've shot a bunch of steel ammo and back in the day was logging exactly how many rounds through each weapon and any effects on extractors, chamber, bore, etc. Got tired of it after 9k rounds through an HK USP 9mm and Noveske Recce after 11k. Lol.

My take on it all is that I shot steel because that's all I could afford and wanted more trigger time between deployments and on top of what Uncle Sam supplied. I closely watched springs and extractors for wear incase I needed to replace them. Once I could afford brass and the prices have gone down over the last few years I shoot commercially loaded and stage all my brass for reloading.

Oh and the newer braunaul is better laquer coating then circa 2005-2008. Same with Wolf's polycoating IMO.

Here for those wanting the sba3 pics. I have a sbr’d Lower but  it’s nice to have another one to travel with. Without all the hassle.

Yep! Doing that! Can you use a standard carbine tube with it? I'm thinking the tanodized one that I have?

I saw your painted lower and FDE Magpul grip and PMAG combo and immediately thought of asmig's Block II build...

Yeah mines on a colt 4 position.

Perfect, thank you!