Originally Posted by JLA
I use a generic seating depth of .010" off the lands for bolt actions and maximum listed COAL for semi-autos. Once I have obtianed a good load I then adjust the depth in increments and test them. Almost always end up within .005 of the original .010 off if not .010". thats the figure I find that works best in most rifles.
Semi autos are different. I have found they sometimes like the bullets waaaay off the lands to shoot well.
I have found that a rifle likes what it likes and have found no other correlation. I start with the bullet jammed into the rifling and back up from there. I have a 6.5 X 55 Swedish Mauser that will only shoot 140 Bergers if they are actually pushed deeper in the case by the rifling themselves. It shoots a ragged hole that way. If you back it off ANY, then it is 1.5 moa. The only negative is that once you press down the bolt, you have to shoot it or dump powder out of the rifle and knock the bullet out with a rod.