Couple things.
Speer 400 grain JFP. I found accuracy around 1550 - 1600 fps. I got 3-shot groups under 0.7" or better, center to center at 100 yards, with 52 grains of H4895, Winchester brass, and Federal 210M match primers from a stainless marlin guide gun. It shot very well in an 1895 GBL and in an 1895 Cowboy rifle.
RCBS 405 grain flat point, gas checked, sized 0.459. Actual weight was around 425 grains. With 47 grains of IMR 3031, again, WW brass and Fed 210M primers, groups were around 1.5 inches at 100 yards with the ss guide gun. Didn't shoot many (any?) in the other two.
For lower recoil yet, the Remington 405 grain factory ammo shot under MOA in 3 of the 5 Marlin .45-70s I've owned.
