Low pressure or black powder load for 9.3x74 ?

I recectly saw an ad online for a J.P. Sauer hammer drilling that was supposed to have a 9.3x74 rifle barrel. When I asked if the seller meant a 9.3x72 which would have been more likely he stated it was a 9.3x74 meant for black powder. I thought the 9.3x74 came out in the early 1900's as a smokeless caliber. Any body hear of an early low pressure load? Wish I could buy the drilling since I already load for the Ruger No.1 in that caliber. The seller said it was sold to him as a 9.3x72 but it slugged .366 and you could camber a 9.3x74.

If proofed pre-1939 more likely a 9.3x72R. Hammer gun suggests likewise. Possible it could have been rechambered to use 9.3x74R, but that doesn't mean that doing so is safe. I would try a milder load with 265-275-grain bullet at .38-55 levels, about 30 grains of RL7, 3031 or 4895 and see how close together the barrels are regulated at 50 yards or metres.

It's a drilling so just a single rifle barrel. I have a plain base cavity in my NOE 280 gr. mold so I could easily loads some low pressure loads. I don't think I will be able to sell off a few guns to get the money for this one any way. I agree that it is much more likely a 9.3x72 except the seller swears it was sold to him as a 9.3x72 but turned out to be a 9.3x74. I once bought a no name german drilling that the seller said was 12 guage but turned out to be plainly marked 16 so I guess anything is possible.

I've known old German gunsmiths who only owned the 9.3x74R reamer and used it in both modern and old guns to save money, and simply marked the older guns for their appropriate caliber, sent them off for proof, and they came back OK and were "officially" 9.3x72Rs from them on. I expect yours is one of those.