i shoot a 22in. .45long colt barrel. though i,ve never shot a bear, i have shot many big hog,s. it knocks them down like a truck hit them! and a few deer. the .45 shoots flat enough to 150yds. but it recoiles pretty hard in the heavy weight bullets. (lbt lfn. 325 and 350gr.) the 45-70 would be more of a good thing on the killing end, but also more recoil! at one time i thought of the .45 barrel as a holdover choice until i could afford a 45-70 barrel. remember, it was one of the all time great buffelo cartriges, but after 10 years of use, the .45lc is my heavy!
good luck