Keith,
They were both proofed for 8x57. The proof pressure is tied to the cartridge, not to the rifle. The 91-96 mausers or m88 don't have the third(safety)lug,but that only comes into play when(if) the main lugs fail.The safety lug doesn't bear against the action under normal conditions.I have heard it said, "If you haven't blown one up, you aren't having fun yet." You will likely disagree with the fun part, but at least it was exciting.
Mike