Small sample size, but got my cow last year with a .270 and 140gr Accubonds, and I got a cow two days ago with my 6.5 Creed and 140gr Accubonds. The .270 bullet busted some shoulder bones and wound up under the opposite side skin. The 6.5 CM bullet nicked the very back edge of the lower scapula, blew out about 2.5" of rib on the entry side, went through and exited. I would expect a .280 with good bullets to do just as well.
