I am new to muzzleloading also.I was told to start with 50 grains of 2f powder in a 50 caliber and increase the load in 5 grain increments until I find the most accurate load.In my case,with a 1 in 66 twist barrel,that is 70 grains.My only concern is will this have enough power to kill a deer at 75 yards.I'm shooting the round balls because nothing else is as accurate in this slow twist barrel.
If you can tell me the barrel length Cal of your gun Round ball weight what you have the gun zeroed at in yards & what powder your using. I could give you a educated guess how many ft/lbs it will have at any given yardage to your zero point. Also how fast it is moving in FPS or feet per second. Being a lead ball is going to limit killing range tho as it will drop fast & bullet weight retention is not very good in 90 to 100% lead bullets - balls.