Is this to thin to be safe?

[Cold Spring]

I would shy away from it but with those measurements in the forward 1/4 or so of the barrel it’s probably ok to shoot light loads IF IT DOESN’T have tight chokes. How tight is anyone’s guess. I once had a C Grade Fox 12g with Krupp steel barrels that a hacker “gunsmith” bored out beyond what we’d agreed to, and the remaining walls at the choke leades were .018 and .020” thickness. It only took one round of clays (50 shots each barrel) with Remington Gun Clubs before I saw bulges at the start of both chokes which were both Full at 36 and 40 points of constriction. Barrels ruined, lesson learned.