A few years ago, Jim Taylor-GunWeek did quite a bit of work with the 58 remingtons. He found that 37 grains of fffg would fit in the chambers under a ball. I've used 35 grains of black and substitutes in Remington and Colt Copies and seem to get the same High 1,000 fps range that he recorded.
Remington
Load .451 Ball Velocity Spread 5
35 Grain Swiss FFFG .454 Uberti 1089 33
Various Colt 1869 Army Replicas
Loads 140 grain Ball: Velocity Spread
28 grain FFFG Colt Second Generation 822 FPS 55
28 grain FFFG Uberti 871 104
35 grain Goex FFFG Colt Second Generation 855 37
35 grain Swiss FFFG Uberti 1031 48
22 gr./vol. Pyrodex P Uberti .457 Ball 725 25
22 gr./vol. Pyrodex P Uberti .454 Ball 712 27
28gr/vol Pyrodex P Uberti 841 54
35 gr./vol. Pyrodex P Uberti 1047 116
35 gr./vol. Pyrodex P Uberti
with felt wonder wad 1055 69
28 gr./vol. American Pioneer 506 57
Lee 200 Grain Bullet
35 gr./vol. Pyrodex P Uberti 967 46
28 gr./vol. FFFG Uberti 753 46
FPS= Feet Per Second
