Ahh, the loaded question.
So, up front, I shoot a bolt that is in the suspect heat treatment group.
Its been shooting for along time though we are not sure in what gun! (long story I won't bore anyone with, its possible it got mixed up with another gun that was shot for a long time).
One thing to keep in mind first and foremost. If someone says the pond is safe and you see major cracks in the ice, you need to rethink. In other words, if the gun has any issues, then don't. Advice does not cover up a previous problem that common sense says you should not have gone there with. That said.
I have extensively researched that issue. As noted above, at this point, they have not only survived close to 100 years of use, they have done it without failing.
The Marines did not turn their in, they continued to use them. No one has reported there were issues that stood out. That was in some of the most gruesome combat operations ever conducted.
Keeping in mind that there are always failures, some notable ones were as a result of greasing bullets under the bizarre thought process it made guns more accurate.
Read the following
I think Hatcher ran tests and failed to blow any up and he went way beyond normal proof loads.
One piece of advice I did come across that I think has relevance is watch the light loads. It sounds counter intuitive and there is disagreement on the subject, but it is felt that too light a load with some powders can result in an erratic ignition that then causes a pressure spike in excess of even proof tests. So run your idea past the reload group here before you do it.
Good luck shoot long and prosper!