DSM, When a smith laps a barrel, it is done before chambering and crowning. The barrel gets big on each end is the reason when stopping and starting strokes. These ends are cut off. Using the Bullet Guru's (Marshall's) process is the best for a completed rifle. Wherever holes are drilled or dovetails are cut, the barrel wall pinches in. The prescribed firelapping process takes all this out and you make the perfect barrel. If a person don't care to do it, mediocrity prevails.
