I agree with what Captchee wrote, and many others, as well.
From my own experance, I have taken a lot of deer in the last 45+ years with 45, 50,54,58cal. rifles and 12ga. smoothbore muzzelloading shotguns, both flintlock, and caplock. Most everyone of them went down quick. Some right where they stood, and others ran off a few yards before going down. Only one went 70 yards before dropping, and that was because I hit him a little higher then I planed to. I've used balls made from soft lead, med. hard lead, and hard lead, and didn't see a whole lot of differnce in how they went down.
Like they said above, It's where the shot is placed that counts. I don't take a shot unless I'm 99.9% sure I can put the ball where I want to put it. By doing it that way, I've saved myself a lot of tracking jobs
Just my two cents of how I do it, someone else may do things a whole other way, and come out with the same results.
How ever you do it, Good Luck with your shooting, and have fun with it.