Here is some comparative data. This is in a flintlock. In a percussion rifle, I use Hot Shot nipples and the 5 grain black powder booster that Hodgdon recommends in their printed loading manuals. You can look them up on the web, call up Hodgdon Triple 7.
The rifle is a .58 Green River Rifle Works barreled flintlock Hawken fullstock I built.
If you can't read it, the target on the left is 90 grains of Swiss 1 1/2 with a .562 ball, 6 shots avg 1507 fps. Next, 90 gr Triple 7 2F with 5 gr Goex 2F booster, 1727 fps. Then 100 gr Goex 2F, 7 shots avg 1525 fps. Right, 100 gr Triple 7 2F, 10 shots avg 1801 fps.
Not pictured, 80 gr Goex 2F gave 1331 fps for 6, 80 Swiss 1 1/2 1432 fps for 5, 80 Pyrodex RS 1488 fps for 5, 80 Triple 7 2F 1636 fps for 5 and 90 gr Goex 2F with .575 ball gave 1441 fps for 6 shots. The reason for six and seven shots is, I don't wipe the bore after shooting nor clean between changes of powder. Frequently, the first shot with a changed powder will be slower and out of the group.
Fifty grains would be a mild load. 90 would be a good hunting load. 100 thumps my poor old aching shoulder joint pretty good, especially 10 shots. I could have gone up to maybe 140 grains, but this was enough for me.