If you look at it,we need to pay more attention to the first nine inches of the barrels. Thats where all the major pressure occurs. Thin barrels past that become more of a dent risk, than burst risk, without an obstruction.
Been thinking about proper loads for an early 1910-1915 20 ga. pump gun . 2 1/2 is no surprise. But it has Krupp barrels with good wall thickness so maybe pressure is not my major issue. Its what kind of recoil can the action and stock withstand. Some of these old pump guns dont have the strongest lockups. Food for thought. Maybe a nice 7.5-8k psi load at 1100-1150fps. I suspect original loads for a 20 were greater than that.
