Just checked an article I wrote for GUNS magazine last year on using .22 centerfires for big game. I researched the rules in all 50 states, and they're legal in over 2/3, and legal for some kinds of big game in several of others.
As I noted in the article, quite a few hunters (usually older) have an immediate gut reaction against hunting deer with "twenty-twos," probably due to .22 rimfires. The same hunters are usually fine with using 6mm's, though sometimes (because they're old enough to remember the day before 6mm's) desire a minimum of .25 caliber. Guess what? The difference in diameter between a .224 bullet and 6mm or .25 is about the thickness of human fingernails, though of course depending on individual nails.
“Montana seems to me to be what a small boy would think Texas is like from hearing Texans.” John Steinbeck
