The idea of "light" loads in any caliber doesn't make a lot of sense where big game is concerned, IMHO. For big game I always use a charge well above the state's legal minimum, 50 grains. Most of my deer killed with .45s were killed using 80 grains of 3F which is a fairly stout load. Only one ball was ever recovered. My farthest .45 deer was with 65 grains at 75 yards. The ball went clear through and the deer ran about 60 to 70 yards.
In my .50s the charge was always 100 grains of 3F. I recovered several flattened balls over the years; most were through and through. The two longest shots were right around 100 yards (+ or -) with pass through. Nowadays I use 60 in the .45 and never go above 70 grains which gives around 1800fps. 70 grains seems to shoot well at 100 yards in my .50 for around 1700fps; I wouldn't hesitate to hunt with 60grns (just under 1600fps). Black bears are common in my area so truly "light loads" are out.