Ken,
I believe I fall in the over cautious category. smile
My hunting buddy shoots LN/LR Win 12ga all the time in his Purdey hammer damascus. We often shoot side by side at the skeet range with his setup, and I'm not one bit uncomfortable.

With that said, my situation is a bit different. A VERY light damascus Flues 20ga.. Barrel walls were checked years ago but I can't remember the minimum dims. I feel over caution is in the best interest of friends, and my left hand.

Bill Johnson