So if you use a "hard" alloy, you are going to likely blow a nice, clean hole right through your prey. Hard lead bullets = penetration. Soft lead bullets = deformation. You want hard lead bullets on very large, dangerous game, to reach the vitals, especially since it tends to be safer to shoot them farther away. However you trade deformation and an expanding wound channel for that penetration. On the other hand if you up the velocity quite high on pure lead, the deformation will happen faster than at a moderate impact speed, boosting friction and actually slowing down the projectile faster.
When you say "explosive" modern bullet, IF you mean it fragments then
no that's not desired. IF you are taking
hydrostatic shock, and the "explosive effects upon impact" that's a bit different. It's NOT from the bullet design. (Modern bullet designs want massive deformation but no fragmentation, to give the hunter the largest permanent wound cavity.) Hydrostatic results are from the random chance that the impact of the bullet at very high velocity coincides with the heart-beat of the animal. If the bullet impacts when the heart is at full contraction, you get the best chance at hydrostatic impact effect. And if not, then you lessen the chance. You're not going to get those velocities from black powder.
THAT is why the calibers are large and the bullets very heavy. You are relying on inertia at impact to overcome the friction of the animal's body.
If you're not getting a fast kill with the PRB, then you may be defeating yourself. I've had many more BANG-FLOP situations where the deer dropped in its tracks or dropped so fast that the animal was within 20 yards of where it was standing when hit. I've also had to track a lot of deer hit with modern ammo large distances.
Broadside there is the double lung shot, thus
Some go for the heart too with this, and aim lower, but I like to eat the heart, so I only go for lungs. The objective to be to hole both lungs and exit the opposite side, deflating the lungs in an instant and having a good blood trail if needed. I've only had to track one deer hit thus, and he was jazzed having just run over to the farm where I was because across the road they were having a fox-hunt. (Horns, and hounds, and mounted hunters, and what a racket!) So this is a good choice but..., sometimes adrenalin doesn't make it the best choice.
IF the deer quarters toward you, the shoulder shot has the best chance of dropping the animal where it stands.
This smashes bone in the shoulder and very often the ball deflects into the spine.
There are other shots of course for very competent marksmen, but with only one shot I prefer either of the above.
The only other possibility, is there have been instances where folks have tried to duplicate the velocity of the modern rifles, and that's not how this tech works. Very high impact velocities will cause massive ball deformation and the friction may actually prevent proper penetration due to the deformation.
Historically the folks that depended on flintlocks and caplocks for food, quite often only worked up an accurate load that "cracked" when fired, and stopped experimenting there. That crack meant the ball was going supersonic (they didn't know that, they just knew the results were better when the load made the ball "crack" going down range) So a patched round ball only doing 1100 fps is pretty much quaranteed not to be supersonic at impact. It seems counter-intuitive, but it does work.
LD