The states I've hunted in mandate 50 grains of powder as the minimum and .44/.45 as the minimum caliber, at least during the ML season. I always use a bit more powder than that in any of my deer rifles. Oddly, or maybe not, I've recovered more .50 ball from deer than .45. I don't know what this proves, if anything, it's just what I've experienced. Most of the deer did run a bit but never far. There were also quite a few DRTs. But, then, .45 was the smallest round used.