the 10MM is a devistating round, and has actually been used on several occasions to bring down large brown bears in alaska and north america. ive killed several deer with a 10MM auto. also, while its not advertised or advised, i regularly shoot 40 S&W out of my glock 20C and omega without an issue. still very accurate. i use the 40 s&w to plink and the 10mm to hunt with, or for woods defense. great round.