I have two Browning semi auto doubles, one came with a plan barrel and one with two ribbed barrels. I wish to keep the receiver that the single barrel in on (it's way nicer) and put the two ribbed barrels from the second one on it. They refuse to completely insert into the opposite receivers. Is there a tweak that is needed or do they not interchange. It is the last 1/2 inch that won't insert. I do not know if it is in the forearm or the receiver. I have looks at them and can see no difference.