I read the handi basics, tried a couple things and still couldn't get my used 45/70 barrel to latch up on my sb2 reciever. Took the gun along with the original 308 barrel to a local gunsmith. He did some measuring and came to the conclusion that the diameter of the 45/70 near the breach was too large to let it close enough to latch. Anyone have tips other than sending it to manufacturer?