I just picked up a Browning Safari .375 H&H receiver and bolt that a friend had replaced due to being advised by a gunsmith that the bolt was "set back" or upset.
I expected to see the bolt lugs peened back into the recesses in the receiver but what had actually happened was that the lugs on the bolt had been peened back around a .010 -.015" or so where they contacted the receiver. Remember this a .375 H&H length action so much of the bottom of the shoulder in the receiver for the bolt locking lug is removed to lengthen the action for the .375 cartridge.
From this example it appears the weak link in reworking a 98 Mauser action is not the receiver but rather the bolt. I thinking just replacing the bolt body would get this action back up to shooting condition. The other option is to just rebarrel it with the proper headspace and keep on shooting it - the lugs should not have been waekened to any significant degree since the steel is relatively soft.
Has anyone else the bolt lugs get upset or peened back in 98 mauser action? The pressures in a .375 are not any higher than any other magnm case so it could happen in any caliber.
I should mention that the person that owned this rifle for several decades and hunted and shot it a LOT - probably much more that any of us would.