First, check to see if you really need to do it.
1. Get a Q tip and stick it in the bore from the muzzle end. gently pull it and see if anything catches the fibers. If it does, you have burrs and they should be either machined or lapped out. If the swab comes out the way it went in, just continue to march and leave it be.
2. If your shooting and kicking an occassional flyer out of your groups this can be caused by a bad crowning job.
Your bedding might also be junk and/or your ammo isn't tuned to the rifle and/or your scope sucks.
Nothing is ever simple is it?