From a target shooting (benchrest) standpoint I make 'em quite hard as i have a large supply of Lino and Monotype. This works well if you have established your proper dia. bullet. For Hunting I alloy them based on the velocity I will be firing them at. My favorite hunting rifle is a 50/90 Sharps w/black powder and i use a 30-1 mix of lead/tin, for me, higher velocities call for more tin or lino. The problem with hardening them too much is they become brittle and can shatter on heavy bone, at least they did in our tests. Bullets made of just lead and varying amounts of tin tend to hold together better and you get that classic mushroom bullet look, when you dig it out of your Buffler.