Two questions for those who have done an AR-9 pistol build
1. If one is building an AR-9 and has a lower that takes Glock Mags, will any pre-built upper work, or do you need to find one that will work with a glock mag lower?
2. These have blowback actions - is a standard AR buffer and buffer spring usable, or do you need a setup specific for blowback setups?
Any other "gotchas"?
I just got done building one but a PCC not a pistol.
1. It's the BCG that needs to be compatible from what I researched. Supposedly, the Colt BCG will work with Glock mags also but not the other way around.
2. They say you need a heavier buffer but I have seen people that have used a regular carbine buffer and spring with no problems.
As I said, mine was built as a PCC but I wanted to use a rifle tube to put a wooden stock on it. I used a 308 spring and buffer in mine and have had no problems at all.
3. What I found out is that you need to get a dedicated AR-9 trigger. I bought a Rise 140 trigger for mine and it said it was good for AR-15,AR-10, and AR-9. The third time I shot it, it started shooting 2-3 bursts every now and then. Don't get a trigger that lists the whole gambit of AR's, get one that is only for AR-9. With the blowback, the other triggers don't have a long enough delay so the hammer doesn't reset/lock back all the way which causes it to burst shoot.
For me, the trigger issue was my only hiccup. Will be buying a dedicated AR-9 trigger pretty soon.
