I took my new AR to the range yesterday to sight it in and I ran into a problem. The bcg is way too tight in the upper. With the bolt installed, the carrier won't move freely in the upper. I tried a different bcg in my upper and it was fine, and tried my bcg in another upper and it was too tight. But without the bolt, the carrier drops right in. I even tried a different cam pin in my bcg and it didn't make any difference.
The upper is an LMT and the bcg is a new Stag/CMT. I was planning to e-mail Stag, but I thought I might ask here first and see if this is something easily fixable, or a common problem.
Anyone?