Doug, there's no real reason why you could not shoot 3" shells in 2 3/4" chambered modern guns, from a pressure standpoint. SAAMI pressure limits are the same for the two. But there's no real reason to do it, since the 2 3/4" shell is the most common one out there. 2 1/2" shells, on the other hand, are both uncommon and expensive. As for every possible combination of hull and wad . . . Doug, are you unfamiliar with reloading manuals? The powder companies do that for us. If I work up a load that's rated at 7,000 psi, using the exact recipe in the manual in question, how is that worse--in a 2 1/2" gun--than if I fire a factory 2 1/2" shell that generates 9,000 psi? Your typical British 2 1/2" shells, for example, will tell you that they're just fine in guns with 2 1/2" or 65MM chambers, proofed at 3 tons or 850 bars. So marked, right on the shell box. Well, guess what? Service pressure for an 850 bar gun, per the British Proof House, is about 10,700 psi. Which means there can be some pretty darned hot 2 1/2" shells out there--far hotter than my 7,000 psi (or less) reloads.
Geno, you're pointing your finger at the wrong culprit. ANY vintage gun should be inspected before you fire ANY shell in it, regardless of whether it's a 2 1/2" shell in a 2 1/2" chamber, or a 2 3/4" low pressure shell in a 2 1/2" chamber.
Last edited by L. Brown; 07/08/10 02:42 PM.
