I've shot a bunch, but never at game- in 54 and 58 cals as well as 50. They've taught me several things. You want a twist rate of 1:48 or faster. You need to cast from pure lead. You need to cast really clean, fully filled bullets. You want a decent lube (I use 2 dips in LEE Liquid Alox). And, in all the guns I've tried, best accuracy is found with a lubed felt wad between the base of the bullet and the powder.
I'm a round ball hunter, but I love to dink around with stuff. They've been great dinking fun for me, especially for long range shooting. I have no doubt they'd be fine on game, but I just haven't gone there. Yet, anyway!