Brownells - Jack Rowe, Master Gunsmith Series, Bore Size and Proofing, Part 4 of 6
This video details the critical process of measuring shotgun barrel wall thickness, a key factor in determining a firearm's safety for modern proofing. Instructor Jack Rowe emphasizes a minimum acceptable thickness of 20,000ths of an inch, with 25,000ths being preferable. He also explains how to interpret proof marks, distinguishing between black powder and nitro proofing, and highlights historical practices that could lead to thinner barrels.











