Relative to a post on another BB, I was just rereading what Sherman Bell wrote in his "Finding Out For Myself: Long Shells in Short Chambers" piece in DGJ (Winter 01). I'd forgotten that Bell did conclude that while lengthening the forcing cone usually reduces some of the (relatively modest) pressure increase that results from a longer shell in a shorter chamber, lengthening the chamber reduces it even more. But then the question becomes: Is the pressure reduction gain offset by the loss of steel in an area where the pressure is very high? Not to mention the fact that if you're dealing with a Brit/Euro double, lengthening the chamber without reproof renders the gun out of proof. Although the latter is a somewhat moot point here, since the gun is a sleever--which means it had to be submitted for reproof after sleeving. But if the chambers were going to be lengthened, the time to have done that would have been at the same time the gun was sleeved, at which point the gun could have passed proof both with the longer chambers and as a sleever.
