I have a Match Grade Machine custom 22" .25-35 barrel on a G2 Contender carbine which shoots Barnes "unleaded" (required here) .257 bullets very accurately. Has killed two blacktail bucks (as you may know these aren't exactly huge), one desert mule deer (much bigger) and two wild pigs (one at 269# with guts and blood out). None went more than 20 yards from the spot they were hit. Longest shot (mulie) was about 120 yds, most much closer.
I suspect that even at the safe pressures for the 6.5x52R drilling these bullets would work just fine, with similar results. (And you wouldn't be hunting with a butt-ugly gun like my G2....).
