Some people care a bit too much about "proof". I proof mine with a wall thickness gauge and a bore micrometer. If the ten bore with 89mm chambers had reproof marks, that would mean a palm full of spit without measuring to see if the walls were OK. Guns with .018 wall thickness make proof, but should we be buying a gun like that? Thousands of guns with proof marks and reproof marks have been incompetently struck afterwards. By the way, the Pigeon Gun at WLM would have a half dozen buyers the first day if it didn't have 28" barrels.