I totally understand about wanting to drop it in it's tracks. I personally would not risk a high shoulder shot on an elk with a muzzle loader. for one they are not totally accurate as a modern rifle. If you should hit the shoulder blade, I don't know if it would penetrate much after. I think I personally would go for a heart or double lung shot. Of course everything depends on your scenario, how close, how good of a shot are you, how much property are we talking, and such. Good Luck I think you're doing the right thing.