Reviews & Ratings for CMMG, Inc 9mm Barrel and Bolt Carrier Group (BCG) Kit — 15 reviews — Page 1

A whole new way to enjoy that affordable 9mm goodness. Friend got the same kit and told me how great it was, but I still wasn’t prepared for… well, how great it was. Top shelf engineering and quality. Installed in your favorite brand upper, along with a pistol or sbr lower, and you too can experience the awesomeness!

Got this and was very excited, have never been able to get more than 4 rounds to fire in a row!
I was a PCC addict had so much hope for this.
I have an Sig MPX, an APC 9K an Aero EPC9, and a Stribog 9, all run flawlessly.
This was the biggest disappointment of all my weapons. My APC doesn’t like steel cases but runs with brass perfectly. This CMMG runs on nothing.
The weight kit doesn’t have any bearing on the function of it so more wasted money.
Maybe a complete gun from CMMG will run but the build is a huge waste of time and effort!
Good luck if you but it!

What can I say? The Radial Delay Blowback works exactly as advertised. Softer recoil, less gas in the face, and best of all, it works with any buffer setup you like, no more 20oz+ buffers and BCG weights and all that so it's much lighter.

There's really no reason to build an AR9 type setup with any other bolt/barrel. It works as advertised, lessening recoil, lessening gas, lighter buffers means lighter gun overall, possibly the best drop in upgrade you could ever make to a PCC.

Buying this barrel/bolt combo will give you the softest shooting 9mm carbine available. Just add a mil-spec Ar15 upper, any handgard, and their 9mm ARC mags and your all set to slap this on your standard Ar15 lower. The CMMG 9mm ARC mags fit and work in any mil-spec lower. This fixes the hard, stinging kick you get with a regular blow back 9mm carbine.

Do not do it.

I know what you're thinking "But C3Junkie said this would be the best set up for my AR9" Yep. We all read those posts. Feel free to trust him like I did, after all, I'm just some random reviewer, but let me tell you what is going to happen: you are going to drop hundreds of dollars on this, plus whatever insane trigger you are trying to run, plus gunsmithing time/fees to get it installed, plus the cost to cut and re-thread this barrel, plus a new buffer, you are going to gut a completely functional direct blowback AR9 and install this... thing. And for about 200-400 rounds it's going to run great. Then, it will one day just, stop ejecting. You'll try different buffer weights and different ammo types and you'll clean it and lube it and you'll sit there at the range clearing double and (inexplicably) triple feeds wondering what went wrong and feeling a little silly. Then you'll get online and start googling, and lo and behold, other people are having the exact same issue. So you'll start reading posts about ejector springs and extractor plugs and realize that CMMG is not going to do anything to help you because "you should really know how to tune your own AR9 at this point" as if this were user error. You're going to come to the conclusion that you are just going to have to replace the ejector spring once every few hundred rounds, You'll order a spare parts kit and some new tools that you'll need to do the replacement and you'll spend a few minutes trying to conv...
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This product and CMMG’s customer service are a 1 star all day. Works pretty good for this first 100 rounds. Then, small chunks of metal started coming off the bolt face. I personally will never purchase CMMG products again

I built the 8" kit into an Aero Precision Receiver/Handguard, Stealth Recoil Spring, and SB PDW brace. Out of 500 rds, we had one failure to eject, but the round sounded weak when fired, so we weren't surprised. No squip, fortunately. The recoil is light, even for my 78-year old mom who loves shooting it. It's cycled all kinds of brass and steel case, as well as hollow points. I highly recommend this system.

I pick up this CMMG both barrel kit to build my AR9. I pick the 8 inch barrel. High quality, the Bolt and bolt carrier group is perfect. They have a spring behind the bolt and a round cam pin. It’s a little different but other than that it is perfect. I highly recommend this product

Quality control is horrible, barrel finish was poorly done. About an 1 inch long noticeable blemish on the barrel right where it sticks out from the hand guard. If it didn’t take almost 1 month to get delivered to me I would send it back but I really do t want to wait any longer. $400 order and that’s what you get....