Finally standardized in 2016, more than 60 years after Roy Weatherby first began playing with the idea, the 6.5×300 Weatherby is yet another example of too much of a good thing. The problem Weatherby could not get past in the 1950s still exists, such a large case using such a small bore simply does not work well with any existing or feasible propellant. Compared to the 26 Nosler, performance is indistinguishable. Comparing it to the 6.5-06 is enlightening. If both have 30-inch barrels and are loaded with the best available propellant at 65,000 psi to launch the 153.5-grain Berger bullet, the 6.5-300 gives 133-fps higher velocity using 28% more propellant while generating 27% more recoil. As to barrel life, the 6.5-300 Weatherby will almost certainly be better than the 26 Nosler because the Weatherby offering has a reasonably long case neck and the Nosler offering does not. But, to many big game hunters, barrel life is of no concern. So, those interested in the last measure of long-range performance from a 6.5mm bullet might find the Weatherby offering a superior choice. As a hunting round, the Nosler offering has the edge because it works in a shorter action and the conventional bottlenecked rimless case is easier to load into a box magazine and usually feeds through an action more smoothly. As was a host of standard belted–magnum cartridges, this case was derived from the circa 1912, 375 H&H.