Briman, it is not too unusual to find Moisin-Nagant bores that are somewhat oversize, and it seems yours is one of them!! What condition does it seem to be in? Are the lands and grooves clear and sharp? If so, it is not necessarily worn out, just a little on the large size. Because of this, it may require .311-.313 bullets to shoot accurately. It might also do well with as-cast .311-.314 diameter cast bullets.

Keep yore powder dry!!