Cause and Effect of Ring in Rifling Near Muzzle
I bought a 30'06 rifle with a small ring, I can see it from the muzzle end and feel when an oily patch is pushed through the barrel, in the rifling 3 inches from the muzzle. There was no discernible ring on the outside of the barrel. Note there is a factory front sight band soldered near the ring and there a punch mark on the bottom of the band which was covered by a metal Schnabel end cap. Anyone, know what could cause such a small ring and what does this punch mark mean. I've seen rifle barrels split wide open from barrel obstructions. Even seen one where an optical collimator was still mounted in muzzle when the rifle was fired - shooter was drunk at the time. The barrel is 20 inches long. What effect would the ring at the 17 inch point have?