The .50 will do it, as mine with 80 gr. of 3f and PRB has 3 times. The largest was 500 lbs. Bear are easy to kill. The one I shot this year (230 lbs.) was shot at about 35 yds. over bait and went less than 20 yds. Where we were hunting, they hadn't been hunted in years and were very aggressive (especially with cubs). I had to shoot my flinter off to chase away a sow and 2 cubs. That worked like manure-she sent the cubs up a tree and came my way popping her jaws. Then, talking to her didn't seem to work with my teeth chattering like that :redface: . It made me decide to build a .54, as the extra knock-down would be great. It's devistating on deer. Remember, there's more to hunting them than the calibre. You only need the rifle when everything else goes right! Other than that, go for it. It's great fun!