I am going to be patterning some heavy weight #7 out of a 20 gauge carlson .575 and an SSX. My girlfriend has an 870 compact while I have a full size. I like that her barrels shorter but her length of pull is a little short on me. If i just swap her barrel to my full size can I expect the same patterns? I guess the question is are patterns determined pretty much by the choke and barrel? Thanks for any input.