I know I have seen the mark that looks like T printed over M somewhere, but I can't place it frown

BTW some gunmaking schools which choose the strongest, not the most figured, wood for their top guns. The Russian school is one example, there's a thread a bit below speaking of that; Russian guns, incidentally, had the long (70mm) chamber as standard since 1900s, the rationale being that one can shoot short shells from long chambers but not vice versa. The gun discussed, of course, is nowhere near from Russia, I just give this as an example of variations of attitudes to guns and gunmaking across cultures.