You guys seriously worry about the legality of crap like this? Just shoot the [bleep] deer. The 9mm will work fine. Shoot it in the brain, or if you're worried about the cape shoot it in the lungs. I've finished off many, many deer with a 22 LR or 22 Mag in similar fashion.
So many nanny states... its illegal here in TX to use a rimfire too... I've done it many times though.. Its not like I"m "hunting" with a rimfire, though I've hunted and killed untold numbers of feral pigs with a 22 psitol and HPs.... just lung em and its dead, or brain em... either or.
This isn't rocket science. And sometimes you just end up ignoring the "law" to do the right thing in the instance.
