Keith, another thing to note is double underbolt guns being fitted on the circle (or lack thereof). I recently discovered that almost no shotguns were actually fitted to make contact on the draw, which undoubtably contributes to their going off face faster than they should - they're bearing the entire fore-aft forces from recoil just on the hinge pin. This is the case even with the British Best guns, much to my dismay.
There are very, very few manufacturers who properly fit their shotguns on the circle. Some Merkel guns have a little removeable insert of hardened steel in the draw and can be made to bear on the circle reasonable easily. Fratelli Rizzini guns are properly fitted.
