The chart has some fine print and is not sourced. However it does seem to have some validity in a generic way, even though the fine print does contain a sort of exclusion for testing revolvers based on their smaller chamber capacity.
I say that it's generic because it categorizes a single shot pistol that's made with a rifle barrel blank the same as a revolver of the same caliber that has chamber walls that are only fractionally as thick.
The exclusion indicates that test loads should take such things as the recommended use loads and barrel length [or chamber length] into consideration. And it indicates that test loads should be double the useful load.
No where does it state what pressure the revolver proof loads are tested at by the proof houses.
We don't know what BAR the chamber walls were designed to withstand, so we can only assume that the manufacturers build their guns with an adequate margin of safety.
So we're back to operating on faith.
I don't doubt that the cylinder was strong enough to handle the proof type loads without catastrophic failure that was described in the chrony test firings.
The manufacturers probably know what it takes to make a cylinder fail. Unfortunately we don't.
Are we to believe that a revolver cylinder is capable of withstanding the same amount of BAR as a pistol barrel made from a rifle blank?
I don't know but that's where the fine print comes in.
But the cylinder does appear to be able to handle as much black powder as can be loaded into it despite some folks being uncomfortable with the fact that it was loaded with Swiss priming powder.
If we can accept that the Ruger Old Army can withstand firing chambers full of smokeless powder which it reportedly can, then we should be able to accept that Remington chambers can withstand being fired full of priming powder.
That's probably equivalent to or even exceeds a proof load that the proof houses use to test the cylinder.
But that's where a person's own judgement and faith in the manufacturing, inspection and materials are operational.
Can there be a flaw in the cylinder wall either from the beginning or from repeated test firings?
I suppose.
Whether it's a rifle, pistol or revolver, should there be warnings against self-proofing guns using priming powder?
I suppose.
Should we trust the figures in the chart?
I suppose.
Besides the cylinder, can a revolver be damaged by shooting such proof loads?
I suppose.
Can a shooter be injured by shooting such proof loads?
I don't know.
Anything is possible including injury caused by excessive blow back or due to related parts failure I guess.
Or there would need to be some kind of catastrophic failure due to some kind of flaw that we haven't seen any reports of yet.
The worst that we've seen described are barrels being shot loose from Colt Walkers when loaded with stiff charges of 777.
Is darkerx delusional in thinking that it's safe to fire such loads.
No, I suppose not. He's simply taking a calculated risk that's based on his own knowledge, belief, personal judgement and faith.
He's not asking anyone else to do it.
He only did it because he decided that he could do it safely with little risk of injury.
In that respect he's done it for us and it's nice to know that even a brass frame Remington revolver can withstand such abuse even if only for the small number of rounds involved in the test.
We all want to believe that the manufacturers are trustworthy, that the proof houses are trustworthy and we also assume that darkerx has reported truthfully about his loads and chrony readings too.
So in that respect he has earned mine.
