Yeah, I wouldnt actually try and hit the shoulder...aim behind it.

That said, I have hit dear in the shoulder BLADE and got penetration through both of them with no problem, but the shoulder blade is a fairly thin bone. You hit them in the big bone connected to the blade, then its not a good thing. The couple I have hit in the shoulder have expired IMO no quicker than a good behind the shoulder hit.

Stick it through the ribs.