I mentioned it in my first post but it may be worth repeating.
Lots of military issue Peruvian Mausers in 7.65 Mauser caliber were simply rechambered on their orig 7.65 bbls to 30-06.
So the groove dia in these 30-06 conversions is .312
Conversions were done post WW2.
I've read it was done by the Peruvian Govt and also some say by FN for them. We supplied the ammo post war.
The bbls show their orig Belgian FN mfg proofs and other period mfg markings. If the bbl is orig to the rifle the serial number matches and most do.
The front recv'r ring is notched. This was done during the caliber conversion to allow smooth stripper clip loading of slightly long(er) GI 30-06 rounds into the mag box.
The rear bridge was generally hand stamped ' .30 ' to note the caliber conversion from the orig Mauser round.
The Peruvian crest remains on the top of the ring.
It could be one of these 7.65Mauser caliber conversions to 30-06 caliber that has since had a .7.62NATO insert put into it for convenience of ammo supply.
Those inserts were very common for M1 conversions to NATO cal at one time and 'the thing to do' with a crusty old 30-06 Military bolt rifle,,,who wants one of those after all.
If this is what you have,
Removing the NATO cal insert would leave you with a 30-06 chambered bbl with a .313 groove dia bore of the orig bbl.
I have one of these Peruvian Mauser conversions to 30-06 here now, in bbld action form. Wondering what direction to go with it. Perfect bore but a .312 of course.
FWIW, (Some of?) the Peruvian Mausers have the 'reversed' flag safety positions on the bolt as well.
FIRE position is the Safety laid over to the right side.
