Having dealt with this issue in my shop, after direction from the ATF(BATF&E), you could have the barrels "restored" or replaced if the old ones are under 18" and the overall length is less than 26". I have "restored" a number of A-5's, that were so "fixed-up". The short barrels I then crushed in a vice and trashed. Unfortunately fitting SxS barrels is not like fitting A-5's or 870's. Best of luck. Dr. Bill