You can calculate the maximum amount of Black powder you can burn in a given length of barrel of a specific caliber shooting the patched round ball, by this formula.
Pi( 3.1416) times the radius of the bore( R= 1/2 the diameter ) squared( multiply the radius times itself) time 11.5 grains, times the length of the barrel.
In a .50 cal barrel, that is 28 inches long, it looks like this:
3.1416 x .25 x .25 x 11.5 x 28= 63.23 grains.
Make that a 36 inch barrel, and the maximum amount of powder is :
3.1416 x .25 x .25 x 11.5 x 36= 81.29 grains.
A 42 inch barrel will fire about 90 grains.
This does not mean that you can't put more powder in the gun. It only means that more powder than that and the extra is burning outside the muzzle. With a chronograph, you can see this. The only benefit of putting more powder in the barrel than it can burn is to increase the total mass of the powder, which helps increase the pressure inside the barrel when the gun fires, and give a few FPS more velocity . However, the efficiency of the burning of the extra powder is off set by greater recoil, and you are spending more money for powder that is not delivering you proportionally as much power for the amount used.
If you will do your own penetration test, you wll find that penetration with any round ball is dependent mostly on the total weight of the lead ball, not velocity. The only reason to use more powder is to attempt to flatten out that ballistics curve in midrange, so that the ball does not strike as low at 100 yards, as it would if you used that lower weight powder charge designed for 50 yard target shooting. Usually, the groups size opens up when you use more powder for this purpose, so you have to make a judgment as to wether you want to concentrate on accurate placement, at the longer range, or be able to get the ball to strike an inch or two higher by using the heavier powder charge. I always ask the shooter, are you capable of holding that 2 inches you may save by using the heavier load, using your iron sights? And, How often have you ever seen a deer at 100 yards or further than you had a clear line-of-sight shot at? How you answer those questions should go a long way in helping you decide how much a change, if any, you make in your " hunting load ", compared to that target load you now use.