Few good bullets out there.
Depends on how far your wanting to shoot.
For deer I'd go with the 140 amax, for elk it will work but it better be about 500 yards or further.
140g AB would be a good all around bullet as well as the 140g SST.
I'd try H4831sc, H1000, and Retumbo.
I'm working on my 264 right now with 140g amaxs/H1000. Results have been inconclusive at this point in time due to inconsistency issues. It'll shoot 1/2 MOA one day out, and 1.5 the next, but its due to a lone flyer, everytime.