You might try 6.7 WW231/HP38 with a 200 grain cast bullet of any shape in a 45 Colt case. Or 6.2 grains in a Scofield case. The Frankfort Arsenal loaded a cartridge in the 1890's called 45US. It was Scofield length and had the rim of a 45 Colt. It used a 230 grain lead RN bullet at 810 fps. I have a 1910 version in my collection also, with a jacketed bullet. (If this sounds familiar, it is what Col.Thompson's commission based the 45 ACP specs on). The reason for the 45 US round, was for a single ammo for all the 45 service revolver designs in use. Enjoy your revolver. Ivan