I don't have the measurements at the moment; they are buried somewhere, however, one barrel is full choke, the other is cylinder. It is a gun for birds and small game. I want to use it for Woodchucks. Regarding using 2 & 3/4" cases in a 2 & 1/2" chamber, it is my understanding (though I have not actually read that particular article) that Sherman Bell did some tests to see what effect a 2 & 3/4" shell had on pressure and found a much higher pressure spike at the throat.

GLS: thank you for that link

Question: For comparison, what was the original black powder pressure? (i.e., where does the 7,000 psi limit come from?)

Last edited by KirkD; 02/27/12 08:15 PM.