I've used the 160 Sierra HPBT more than a bit for deer/elk/lopes, it's slam dunk one of my fav's from a big 7. I'd just stay the course with it.
But, if you feel the need to drive a 120 NBT by all means do so. I am sure it'll work just fine.
Keep in mind that driving it @ 3300 will pump the bump up very close to what the 160 would be at 3K or so. (make sense?)
Either load will shoot plenty flat for lope hunting and or whitey's in the open country.
Personally, for woods hunting in Minne I'd maybe just slow the 160 down to 2700 or 2800 and if and when he goes for open country then jazz it up a bit.
Just a thought
Dober
