When I received my last .50, having, I think, a 56" twist since the recently Late Don Getz, (RIP friend) made the barrel for Taylor, I started with 75gr. 2F GOEX and a tightly patched .495" ball. The rifling is .016" deep. After shooting a target with it, I raised the powder charge to 85gr. 2F and am happy with that load, so far, for shooting on our trail through the bush. More rest shooting/testing is in order for that rifle. For hunting, I will be testing that rifle to about 110gr. or 115gr. 2F & I am sure, it will simply shoot better with the heavier charges and oiled patch, than it does with the lighter charges and water-based wet patches I use for plinking.
As others have noted, you cannot compare long range shooting with slugs against round balls. Slugs or conicals can accurately be projected over a long range, much longer ranges actually, than a round ball will even travel. Most calibres of shoulder fired rifles (up to .75 cal. at least) will not even project a round ball to 1,000yards, let alone make a killing or disabling blow at that range.
A round ball is a close range proposition, with perhaps 150yards maximum with a .50 for deer sized game - but only IF you AND the rifle are capable at that range. Otherwise, get closer.
The Hollow Based slug was invented for quick & easy loading over long periods of time and to give longer accurate range shooting, for war purposes. We must ask ourselves, is a rifle designed for long range shooting at our enemies the best 'system' for hunting. To answer that, we must examine the characteristics of each to determine which is best for our end goal.
The conical firing rifle was/is designed for shooting tall narrow 'targets' with a fairly long hitting zone, while animals are short in comparison with long bodies but smallish kill zones. We desire to kill animals quickly and without suffering, while our designs and intentions against our enemies are not so pleasant.
Since a man wounded by a 500gr. chunk of lead going through him, wounds him to the extent he is either killed or simply taken out of the conflict, thus a hit anywhere over the length of his torso from head to crotch including his thighs, is the goal. Due to the sheer height of the target zone, a high trajectory is not problematic, but rather advantageous to our end goal, that being to kill is as much of a goal as is to wound. A bullet, fairly aimed at the centre of mass but striking 10" high, will hit the head, while 10" low will be in the crotch or thighs. Thus, good shot, old chap! The same aim and hits on an animal, however, will miss high or low, or if hitting, might wound in either event rather than delivering a fatal blow. A long, stern chase in inevitable.
The high trajectory that matters little in a military weapon, makes for grave difficulty hitting the killing zone on an animal over relatively short, but unknown distances. Thus, the flatter the trajectory, the better for us hunters. A well loaded round ball rifle properly sighted, will give a trajectory flat enough to kill deer without any holdover or hold under, from the muzzle to about 125 yards - which can be labeled it's point blank range. Thus the ball will be neither over 2 1/2" to 3" above, nor 2 1/2" to 3" below the line of sight. That 6" window gives us lung and heart shots to quite long ranges- IF properly sighted- and practiced.
A minnie(conical)-ball shooting rifle has no such point black range, rather when shooting small 'targets' one must know the range exactly and how to hold the gun to hit it. With the round ball of high velocity, one merely covers the target fairly and hits it where we want it hit.