A bit before he started making his own barrels, Bevan King built a number of 6.5-300 Wby rifles in the late 70s. It was called the 6.5WWH back then, which stood for Weatherby Wright Hoyer, and it would vapourize standard cup and core 140 gr Sierras before reaching 100 yard targets.
Paritions and Speers were the answer, and 400 yards was barely a challenge.
Ted
The 6.5X68S European caliber been around for quite some time.
Perhaps not as powerful as the Weatherby, but a very good flat shooting round.
Even Mannlicher Shoenauer had it in its offering.
it was the terrible parent of the shooting. as i ve seen 2 shoulders and the meat destroyed on european mouflon and chamois while that caliber was used. for the small amount that was a lot but at least they were not lost ...