.223 is an effective round for deer size game, though I wouldn't care to go any smaller. My kids have taken a few deer with their Mini-14s and one still prefers the light packability of his. There are some ARs laying around, but, .30 cal. and up are usually the preferred choice as we do live in bear country. I picked up an AR-10 simply because I can. .308 is adequate for all practical hunting purposes, but, I like my BAR.