Powder Measurements

[Johnny Tremain]

My thought is use the Davenport formula, find your max charge, and work backwards.

My max charge is 74.5, thats my long distance load, anything short of 150 yards, I use 55gr, drops the FPS from 2033 to 1600, but it shoots spot on from 20 yards to 150.

 

[Rifleman1776]

my 54 cal flintlock rifle with a 42 inch Green Mountain barrel has a 1 turn in 72 inches rifling. That is a slow twist. I have found that my rifle groups better with a hunting charge of 90 grains of 2FF Goex black powder

The 1:72" barrel on my .54 cal. Jaeger will not start grouping until I go north of 100 grains of bp. Not a light gun but can get brutal to shoot.