Just finished an AR 9 build and ran into a problem.
Engage colt pattern lower
Engage upper
ALG lower parts kit with ACT combat trigger
CMMG bolt
Pistol buffer tube
Tubbs flat wire spring
Slash's Heavy buffer 9mm buffer 9oz
Brownell's 32 round mags
11" Ballistic Advantage barrel...
Replaced the buffer spring with the Tubbs flat wire and still the same issue. Ran short on time at the range and did not try changing to a standard carbine buffer with quarters. I'll give that a go on the next range trip. I did switch out uppers to a 10.5 556 and it ran fine suppressed and...