I just got a very nice steel receiver Browning Double Auto with a 30 inch full choke barrel and recessed rib. I haven't shot it yet but it begs to play some long range clay bird games. My question about barrel compatibility. Once in a while one pops up on an auction site so I would like to add a shorter barrel with a more open choke. Are they completely interchangeable, interchangeable within the same receiver type (steel, Twelvette, Twentyweight), or do they have to be factory fitted? Mine is a pre-1958 version if that makes any difference.