Grimm used a 12-bore L.C. Smith gun, 7 3/4 pounds, 3 3/4 drams Schultze, 1 1/4 ounce No. 7 shot, in U.M.C. Trap shell.
Carver used a 12-bore Cashmore gun, 8 pounds weight, 4 drams of Carver powder, 1 1/4 No. 7 shot, in U.M.C. Trap shell.
I don't have access to an 1897 Union Metallic Cartridge Co. catalogue, but in both the 1896 and the 1899 the heaviest 12-gauge bulk smokeless powder load offered in the UMC TRAP shell (or any other UMC paper shell for that matter) was 3 1/4 drams pushing 1 1/4 ounce of shot.
Those were some mighty stout loads those old boys were leaning into!!
After the Turn of the Century, 3 1/2 dram loads became available from our North American ammunition manufacturers --
but I have found some of the old gun writers decrying them and stating the 3 1/4 dram, 1 1/4 ounce was a better "balanced" load.