Jeff,
I think your "way over thinking" this issue.
Use the Sierra for practice - if you don't trust them and the NP for game. Simple Simon and it saves money to boot.
Thats what I'm doing right now with my .358, but my major target is elk.
Either bullet will harvest a deer as far away as you can hit it. You might want to use the Barnes Bullet shooters trick and try to involve a shoulder, when the range is long.
JM2cents!
