I would carry my regular carry gun. But of late, I have been carrying a Ruger LCR-22 and really like the little bugger. It just depends on why you want to carry a 22 hiking...?
I carry a 22 for the fun of it and seldom think in terms of "killing a squirrel" to eat. But if actual "hunting" is a consideration, I would choose one that has a 4" barrel or longer in general although I think the 3" S&W M63 is a great little and practical hiking gun for many purposes.