This is all very interesting.
If you shoot straight, both will kill deer neatly out to way beyond the range where most deer hunters shoot--even "big northern deer." I know this because I've done it and seen it done more than once.
JB, way back when my dad had a Savage 110 in 243, it wasn't much of a shooter so for my first rifle he traded it in and I got a 22-250. Even it worked....grin
I really would like to get a Montana in 243.
