Just my thought on that. If you can temper 1095 at 325°, and it's not chippy, I would suspect you did not get it as hard as it should be before temper. Frizzens on a flintlock are usually 1095, tempered at 375°, and they have been known to break. Not often, but it happens. At that temper, a file should not cut it, or at best, using the edge of the file, it may make a very fine scratch, but I really don't think so.