I know of 1 instance where a sxs shooter was useing chamber incerts from 12ga. to 20g. and put a walnut in the right barrel just where the forceing cone should be. The bulge was noticeable all the way around the barrel not just as a weak spot. The gun was a Holland and Holland not a piece of crap, the load was factory not a reload. That's all I know about it. : Mike