I finished building up a 5.45 AR last night. Bolt head was made from a standard 5.56 bolt head opened up to .396. I brought along 6 different kinds of 5.56 magazines (magpul, troy, lancer, and a few different GI mags). If I drop a round into the upper receiver, with the bolt back, the bolt will load and chamber the round. Once I try it with a magazine, it strips the round and the bolt goes most of the way forward but binds up right before it gets to the barrel extension. It appears the round is canted slightly left to right. I know my first order of business is to get a 5.45 magazine. However, I am wondering if I have a different issue. Any ideas?