Whoa... Serious thumper there... There are several cartrides less expensive and easier shooting than this that regularly take grizz and brown bears at appropriate ranges. I'm sure there are sub-.30 cal cartridges that get the job done too, but to keep the list shorter...The gentleman I'm going with is taking his .458 win mag custom rifle
.308 with 180-200 grain bullets
.30-06 with 180-250 grain bullets
.300 win mag witth 180-250 grain bullets
.338 win mag 225-250 grain bullets
.358 win with 180-200 grain bullets
.35 Whelen with 200-250 grain bullets
.375 H&H with 250-300 grain bullets