Re: Suggestions on a BCG malfunction?
Did you just replace the carrier, or the bolt and carrier? Not sure on FA, but some of the chrome plated carriers start as standard carriers, then are plated so their dimensions may be a bit larger than a standard one. #1 , disassemble the bolt and carrier and just slide the carrier in and out of the receiver with your finger and see if anything sticks with just the carrier. Try and troubleshoot one component at a time, the gas tube might be sticking in the carrier key, although if that's the case the rifle will normally still function. If the carrier slides in and out w/ no problem, install the bolt with cam pin and cycle that by hand (this is all with the upper/lower separated). You should be able to push the assembly all the way forward, and retract it w/ just your finger in the back of the carrier. It sounds to me like a tight headspace issue along with a faulty gas system somewhere, maybe a plugged carrier key.
Oh, and if the bolt is also chromed, the headspace may be too tight as their tolerances are also different from the chrome plating.