40x2-1/2" was a designation for the 40-70 Sharps Straight. The 40-70 Ballard was 2-3/8". As Mr. Vicknair said, Sherman Bell and Ross Seyfried have done some great work with IMR 4198 and Reloder 7(?). I use IMR 4198 in all of my blackpowder cartridges, such as 11.15x58R, 11.15x60R and 45-70, to name a few. Good luck!


GMC(SW) - USN, Retired (1978-2001)