I would have to pick the .50 caliber. The .45 caliber might out preform the .50 caliber at longer ranges, but I would still go for the extra weight. Also depending on what and where you might hunt, someone mentioned on this board once, that some .45 caibers were not legal for elk in some states. The .50 caliber is an all around caliber, and the stuff to make it shoot are easier to find up where I live then for the .45 caliber.