Johnson from United States, PA Public Profile

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