The way I understand it is that the .45 is more of a long distance cartridge. Capable of shooting projectiles at higher speeds than some of the others which gives ya more distance in theory. I've only had one .45 in my life and I only hunted with it for a year or so. But I have had five .50 cals. (1 percussion w/ scope, 2 percussion with out, 1 flintlock without, and 1 inline w/ a scope) Just seemed like a more all around caliber. My open sights were great out to about 80-100 yds and had plenty of power. Go with the fifty.