Liked all your comments!The guys you refer to in your episode probably do not understand that while premium barrel makers can guarantee bore and groove diameters within .0001 inch, you are still at the mercy of the deep hole drilling process that can, and will, produce a hole that is not perfectly straight with its own self.If you do drop a 3 1/2 inch long gage pin down that barrel with only a few “tenths” of clearance, and it encounters a spot that is not exactly straight, it will stick.
It's not just the straightness of the blank your dealing with at times.
Guy starts pushing a pin in there and the bore has some dirt/carbon in it from shooting (yes we've had guys pin or slug the barrel after they shot it) or there is some lint from running some patches down the bore or some left over solvents or oil...
You just need one little thing to cause that pin to stick....and presto you have a problem!