Lapping a barrel is a very serious step. I usually consider lapping a barrel as a last step effort when you have tried all other things to make a rifle behave. Granted I have gave a minor lap to a newbarrel that was very ruff.

If you have a new rifle. Shoot a box of maxiball through it. That will usually knock the ruff spots off of it. Also you can shoot roundball to smooth out a barrel. Something I do like to do is take a chunk of Scotch Brite Pad and put J-B Bore Paste on it. Then work the barrel over with that. Usually 50 strokes is a good starting place. It is a very mild lapp and I have noted some dramatic increases in accuracy doing that.