243 100gr nosler part... How far do you think this load would take a 120lbWhite tail ???

I was 100grn game kings figured absolute max 200 for a doe about 150 heavy buck mulie . You ought to be ok out to 225 ,but only if you HAVE to shoot that far and are sure of the shot.

honestly about as far as you want to shoot in my opinion.

as long as you can hit your target, you can kill it

honeslty, i think for any center fire rifle your max should be as far as you feel comfortable.

I agree.

Anything over 100 yards and you will need some type of Ultra Magnum.... sorry, couldn't resist.

Sounds like a skinny deer. You may consider something like a ballistic tip, because you can afford the quick expansion. Anyways,I like partitions too; I'd say as long as you can hit the sweet spot on a deer with that load it should be fine for a 400 yard shot.

First...The Partition isn't your best selection for long range shooting...They are a harder bullet that give controlled expansion...I have killed several out to 300 yards with a 85gr HPBT Sierra GameKing...At that range you will have more internal damage with the Sierra over the Partition...

Farther than most people have any business shooting. But like some have said, for far shots I dont think the partition is the way to go.
I will be honest, my comfort zone is 250 yds and under, not that my .243 isnt effective farther, it's just that I dont think I am.