Longrange338:
I think I follow...
I own a couple 30 SMs. When I develop loads for them, I do it no differently than I do for any of the other cartridge chamberings in my other rifles. Whether they be SAAMI adopted chamberings, or wildcat chamberings.
My 30 SM hunting loads probably operate at higher pressure than the maximum loads listed on Hodgdon's website for the cartridges they do list load data for. I consider my 30 SM cartridges safe, when fired in my rifles.
Likewise, I don't strictly limit my maximum powder charges to those maximums listed on Hodgdon's load data website for the SAAMI cartridges I load for. I develop maximum loads based on primer pocket life, case head ejector marks, bolt lift resistance, measured case head expansion, and fired primer appearance. Those maximum loads are developed no differently than for my Sherman cartridges.
My understanding is the majority of experienced reloaders on this Forum observe the same indicators of pressure when developing acceptable "maximum" powder charges (pressures) for their individual rifles.
Any reloader can blow themselves and their rifles up, no matter the cartridge chambering, if they work at. A fellow reloader I knew from high school welded his Remington 700 bolt to the action, in spite of having reloading manuals, and their prescribed maximum powder charges available. His Rem was chambered in .243 Winchester. He presumed gun powders were substitutable. He substituted whatever powder he had available, at the charge weight shown in his reloading manual.
Some folk would no doubt be better served shooting factory ammo. On the other hand, even factory ammo has been manufactured and retail sold over-pressured. And damaged rifles. Has happened in the past. Will happen again in the future.
Proof has no way of knowing what cartridge their barrels will be chambered for, once they've been shipped out for retail sale. Sherman cartridges, SAAMI adopted cartridges, or any other imaginable wildcat cartridge. This is true no matter the nature of their relationship with elkaholic, or their opinion of Sherman cartridges.
Lots of shooters are obsessed with velocity. Nothing wrong with that. If Proof were to cease barrel sales to velocity obsessed shooters, there would be a notable reduction in sales. No way does Proof want to discourage, or cease, barrel sales to velocity obsessed shooters.
Proof management no doubt has an explanation for their decision. They also have the right to keep that explanation to themselves.