Just bought a Hosford barrel thickness gauge. Neat tool. I should have done this a long time ago. I had some surprises when I measured my doubles. ( all my Smith guns were good) If you shoot vintage doubles even with low pressure ammo it is a good idea. I have one gun that is beautiful, A grade Baker. Bores obviously had been honed as they read.740-42 and still rough. I was suspicious....found a place about 18 inches from the muzzle reading .11 wall. Looks good is not always good. I had not shot the gun. If you buy shooters....consider a barrel gauge. Glad I did. Dk