I have just a short question, I have a Lyman great plains rifle in .54 and I am shooting .540 conicals with 300 grains with very good results with 75 grains of 3FG swiss powder.
I am asking for a rough guess of velocity? Any ideas?
My guess is about 1300 to 1400 fps based on my observation that every grain of black powder is good for about 15 to 17 ft-lb of muzzle energy depending on bore diameter and barrel length and powder brand.
