thermal fit

  1. U

    BCM non blem uppers questions.

    I’ve bought 3 BCM non blem uppers in the past and all 3 of the uppers allowed my barrel to slid in (it was pretty tight) about 1/2 or 1/4th of the way in then stopping and having to be thermal fitted to get it to seat the rest of the way, is this okay? I read somewhere it could be tapered if...