The SXSs that I have measured made in the last 50 years are very close to the chart. Pre WWII some are pretty robust.

I have a Spanish Aramberri 12 ga made in 71 2 3/4" proofed at 1200 kgs. The walls at chamber's end is .082; 4" .096
I have a 3" Ugartechea Falcon 12 ga. made in 72 proofed at 900 kgs. Chamber's end wall is .075 eek I don't shoot 3" in any field gun though.

Last edited by 2holer; 07/09/13 02:10 PM.