BCA barrels?

[bj139]

I took my 16" BCA barrel apart yesterday and lapped the receiver with the Wheeler lapping tool. The receiver was not square to the bore. I cleaned the area with brake cleaner and assembled the barrel and receiver with a thin layer on blue Loctite over the barrel extension. I tightened the barrel nut and checked the gas tube alignment. It is now just slightly out of alignment. It was OK before. I guess I need shims. I found Brownells sells them. I forgot to polish the feed ramps while the barrel was out of the receiver. Can the barrel be removed and reassembled if I want to polish the ramps?