I’m running 125 NBTs for just about anything we might shoot with a 300. Something to keep in mind, at least some the subsonic ‘hunting’ loads, are just mimicking expanding broadheads it would seem. You’re unlikely to get very emphatic kills, at least as compared to the supersonic loads, though stuff will die...it’s just probably gonna be tracking the bleed out, unless you hit CNS. He still might be all over the 6.5....never know.