jimbobborg
Oddball caliber fan
Another thought to the original question. Were these tests available to the countries that made the other rifles? It seems to me that they didn't do these tests because they weren't available.
AR bolts don't need hp/mpt tested
and
Who says other guns don't get tested similarly ?
Help me out with the terminology ; is MPI same or similar to good 'ol Magnaflux?
Its similar. Small differences and to be done properly needs to be done after firing a proof load (IIRC 50% higher than SAAMI pressures) to check it per Mil Spec.
Stay away from Nitrided and NiB Bolts. They often have tolerance or embrittlement issues.