robtattoo
WKR
That result has to be bullet related. If folks are having success with 6.5 creedmoor, 6.5prc, 6.5rpm, .260rem, 26 nosler, and the 6.5-300 is the fastest of them all, then shot placement or bullet construction are the only possibilities and you rules out placement.
As I said, I couldn't comment on the components used, other than assuming it was factory ammo. It could simply be a really motivated elk! I've had numerous bullet failures myself, using VLDs & long range bullets up close. My guess would be that was his issue too. The bullets just going too damn fast.