I have both of Sharpes books will look through them and see if I can find anything.

Any clues on were he put the information ? His reloading book has a lot of information over and above the basics. "The Rifle in America" is pretty good too with some info about actions and suitablity for different jobs.

Give me a couple of days.

Boats

I'd be willing to wager big bux that excessive action springback would cause the case heads to bend, making it difficult or impossible to reload accurate ammo. The later Remington 7x57 actions were redesigned slightly to remove some weak spots such as the thin receiver ring and a probable stress riser point at the rear bottom of the ring where the sidewalls begin, but the basic (lack-of-)support design wasn't changed and the action will still flex excessively.

Regardless of the ultimate yield strength of the action, IMO it's not suitable for any larger cartridge (over 0.375" body dia) generating over about 40-42K psi. I HAVE seen these actions (later 7x57 style) chambered for the 223 Rem cartridge fairly successfully, but bent case heads were still the rule with full loads.
Y'all be safe now, y'hear? Regards, Joe

The posting about 70,000 psi in a roller seemed a bit much, so I dug into Sharpe's "The Rifle in America".  PBS does tell a story about a 70,000 psi load in the 7x57, but he reported the load in connection with comments on the Winchester 54, (pages 255 & 256 in my copy).   On page 319 of the same book, PBS wrote about his 1902 roller and reports shooting many 55,000 psi loads.  PBS wrote "... the very crude military sights were entirely inadequate... This rifle was fitted with a target telescopic sight and is today one of the most valued guns in his (Sharpe's) collection.