I'm in the camp of not trusting 22 shotshells. I have shot them from 3' away and not drawn blood; any closer and you are asking for trouble.
My last snake was shot with a 260AI at 40 yards. Apparently Sierra bullets are stout enough for Arizona rattlesnakes. If I encounter snakes where people typically are found, I tend to kill them. If they are in wild places, I mostly just go around them.
