I recently bought a mint 1903 32 acp made in 1928. When inspecting the bore which was also mint, I noticed a perfectly concentric ring about 1" ahead of the chamber and about 1/2" in length. It is visable to the eye and also the depression can be felt with a cleaning rod patch. Was this likely caused by a bullet stuck in the bore being struck by another bullet fired behind it ? The outside of the barrel is not bulged. Will accuracy suffer because of this ?