just about every gun will knock down adeer if you hit it right. thats just a fact I have seen deer get droped with as little as a 223 its legal in the state of Idaho and techeniqually you can hunt with any center fire in Idaho and montana which includes a 22 hornet i would never hunt with it cause thats almost cruel to the animal but to get back on topic My favotie guns for Whitetail, mule deer and black bear is the .270, 30-06, 3030, and 7mm which is very close to the .270 anyway good luck i guess im done rambling