The next step up

[Dogleg]

but my M-70 has an issue in that the rim of the extracted cartridge catches the case mouth of the top round in the magazine, sometimes stopping the rearward progression of the bolt and making a burr on the case mouth. Crimping only solves the problem if the bullet has a deep crimping groove, like a TSX, an A-Frame, or a cast bullet, but if your jacketed bullet has a knurled cannelure, it doesn't allow the case mouth to form tightly enough to the bullet to avoid catching the rim of an extracted round.

Boomer,
I read that about four times and I'm not sure I'm following you. When I look at my .458 bolt there is .130" between the bottom of the bolt face and the rim when it is properly behind the claw like it should be during extraction. Is the empty case dropping out of the bolt-face far enough to protrude past the bolt body and catch the mouth of the top cartridge? In that case you need a little more extractor tension, something that can be done without tools if you have reasonably strong fingers and thumbs.

If the case is properly behind the extractor it isn't near the cartridges in the magazine, so something else has to be snagging the case mouth. About the only thing that is position to do that is the extractor collar or the groove that it rides in, with conceivably the portion of the right lug that is below the anti-bind slot or the gas block. If it were any of those it should do it whether you were extracting an empty or opening the action with an empty chamber and loaded magazine.