The proof marks indicate clearly that this shotgun was built for smokeless powder. After a thorough disassembly and cleaning, there’s no evidence of black powder. I understand the argument between smokeless vs black powder for older guns but I’m concerned with modern chamber pressures. Intuition tells me that power pressure smokeless loads will benefit the longevity of the gun, but I’ve also read conflicting information online citing the way that old smokeless powders were mixed.
FPS does not equate directly to low pressure. There are loads at 1200 FPS with 7000 psi and other 1200 FPS at 10,000 psi. SAAMI pressures have not changed over time for smokeless powder, but you may want low pressure loads because you want less recoil on your 100 yr old wood