Well if your already stocked up on 30 cal bullets, the 308 would seem a logical choice, plus it can pull double duty if needed for a hunt.
I here great things about the 264 (aka 6.5, but I hate metric numbers) in a number of configurations from 260 Rem to 264 Winmag, & everything in between.
Id venture to guess bbl life would be better with the 30 cal, but launching higher b.c. higher s.d. bullets at decent velocity, would probably go to the 264's for LR paper/steel whackin.
The ultimate right now looks to be the 270wsm using a 165 Matrix with a b.c of aroung 65-66 or 175 Matrix with a b.c. of around 7. Talk about a double duty LR Target whacker!
I'm a huge 30 cal & 270 cal fan, & my guns all have to pull double duty. So my Opinion should be considered heavily bias & in favor of one of those two

Sorry I know you said TARGET not double duty, I keep wandering off the subject. My apologys.
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