Anyone know of testing done on these to determine how strong they are? Wikipedia shows them chambered for 7x57 and some other 55K psi cartridges. Seems high for a black powder action.

Use them for black powder cartridges only; they were produced during the black powder era and are made for the large rimmed cartridge. High pressure loads? Definitely not. Sure it might take it but why take the risk?

France acquired some and re-barreled/chambered them in 6.5x53 Daudeteau, then sold them to Uraguayan military. I believe the Daudeteau pressure is somewhere in the 40-45k psi range.

Thanks.

This one is chambered for the 9.3x57r 360. That's only a 35,500 psi cartridge. The rifle has nitro proofs. It's in good shape. I imagine it should be okay to shoot with 200gr bullet at 1700 fps. Those loads show sub 18K psi.