They'd be good for fixing the lips on a 7.62x39 ar mag when they have feed problems. That's why I hang out hereOh yeah! I had a mild timing problem on one rifle and the small stone files were GREAT for cleaning up the lugs on the barrel extension. Was able to buff the M4 feed ramps and got rid of the harsh edges of a presently-unexplained gouge on the underside of the bolt carrier.