In concept great, in practice, meh.. - CMMG, Inc 9mm Barrel and Bolt Carrier Group (BCG) Kit

Bought the 8".

First bolt self destructed. At first Customer Support said the wear was normal. The bolt had chunks on the leading edge of the bolt missing. This is after 300 rounds. I sent pictures after multiple calls, I sent photo's and they reluctantly agreed to issue an RMA. A week later I followed up with them and yep the bolt was shot they will send me a replacement... toughly a month for this.

The whole time the gun was a jam-o-matic. Couldn't get through a magazine without jamming. I figured it was the bolt.

When the replacement came in, the gun still jammed 1-10 in with each magazine... I called the tech line multiple times, tried everything they said and still nothing. Finally after blowing through 2,500+ rounds testing (not a typo) they sent me an RMA...

They said it runs fine. I asked if they were testing in a AR upper & lower? They replied no in our upper and lower, and now we have a disclaimer stating we do not guarantee function in anything but their upper and lowers. Well that would have been nice to know prior to purchasing.

When they returned my barrel/BCG if figured I had nothing to lose and polished every surface that the round would come in contact with. That fixed the problem. Now that my gun has quite a few rounds on it I asked if I could buy a spare bolt since the one now is high mileage and when it was returned to me came back with significant marring on the lug face. Sales said no, the tech support said yes for $299... First and last product I buy from CMMG.