Wall thickness is a very critical dimension for safety. That’s why you get a component gun smith who has the proper tooling and knows how to use them. Better to be safe than sorry. If you have a questionable shotgun-don’t think about shooting it until this very important criteria is determined.
I have searched the internet for a supplier of these tools that will ship to the UK without success .. any help in obtaining them at a reasonable price would certainly be appreciated.
Vernier Caliper has a clearance problem measuring inside of bore. You must get past the first 2 or 3 inches at the muzzle. 5/8" - 3/4" Telescoping Gage might work. Unless you have a very good quality Vernier I'd suggest you also need a 1" Micrometer. Precision gets expensive in a hurry. Starrette and Mitutoya are reliable makes.
