I think it was the BCG, not out of spec just didn't have a spec of lube. Swapped the charging handle then the BCG from my BCM upper, it was definitely the BCG hanging. Looked like it was packed in some type of cosmoline, cleaned & relubed it and no more snagging. Went to the range yesterday & shot 150 rounds of surplus Yugo ammo, no FTEs or light strikes. I did have some FTFs, I think the ASC magazines may have been the culprit. Started with loading 25 rounds but the first few rounds weren't reliably feeding from the magazines (3 total), dropped back to 20 rounds and feeding was much better. Still had to occasionally use the forward assist but as I ran more rounds thru it the better it got. Only able to sight indoors at 15 yards but shooting from a bench & bipod the groupings looked good (at least for my medicre shooting skills). Loading the mags I noticed the resistance went up considerably after 18 to 20 rounds, hope they loosen up a little after more range trips. Might try lightly oiling the ammo too for better feeding. Overall very happy with Alpha Shooting Sports upper, I think today is the last day that this upper is on sale...