I’ve never owned a6.5 let alone killed game with one. But I’ve shot piles of deer with a 25-06 and a 270 and a 308. I always felt like the 308 hit hardest of them all. Always used cup and core bullets in them all when deer hunting. More often than not Hornady but also Sierra, BT’s, rem core lokts, hot cores and even a few accubonds and partitions.
,I believe the 308 left better blood trails on average than the 270 and definitely better than the 25-06. I’m a big 308 fan and have taken probable 25 different species of big game with one. When the game was bigger I would switch to a 168 tsx. I am confident that a 6.5 with a good bullet would be a fine killer of game.... tsx or tsx’s are wonderful killers of game. Dang.... I think I just talked myself into a 6.5!! Bottom line any appropriate cartridge and bullet placed properly is going to work.

Ben