.264 Winchester Magnum (using Sierra bullets)
Date: Mar 30 2016
The .264 Winchester Magnum was first offered in 1958 in the Winchester Model 70 Westerner, but it was soon offered by most major manufacturers. It is one of four Winchester cartridges that were the original "short magnums" designed to function in a standard (3.340 inch) .30-06 length action. Previous belted case magnums, such as the .300 and .375 H&H, required a long action to accommodate their 3.600-inch lengths. The .264 was advertised to push a 100-grain bullet to 3,700 fps, or a 140-grain bullet at 3,200 fps, but its velocity has been reduced to 3,030 fps. These velocities were obtained from a 26-inch barrel, and like most factory loads (in all calibers) from that era, they were a bit overly optimistic. Recent testing of vintage Winchester factory loads in an original Winchester Model 70 rifle with 26-inch barrel produced 3,066 fps, while today’s factory loads hovered below 3,000 fps.
Nonetheless, the .264 Winchester Magnum became an overnight sensation with strong sales, but that soon ended. In 1963 Remington necked the case up to accept .284 inch 7mm bullets and called it the 7mm Remington Magnum, which was introduced in the Model 700 rifle. It boasted of greater bullet selection and versatility and became an instant success. Although sales for the .264 Winchester Magnum began declining, today it still has loyal followers and is an excellent, flat-shooting cartridge for hunting deer and pronghorn in open country. With correct bullets, it will reliably take elk and moose.
The .264 Winchester Magnum has some unusual engineering that handloaders should be aware of. In order to reach desired velocities, Winchester
factory loads feature a two-diameter bullet. The forward ogive is several thousandths of an inch smaller than the .264-inch diameter shank seated inside the case. The ogive effectively rides the bore, while the shank engages the rifling and fills the grooves in a normal fashion. For this design to work properly, the throat is necessarily short. When using conventional .264/6.5 bullets that are not two diameter, bullets must necessarily be seated deeply to prevent their contacting the leade, (which can raise pressures and often results in a bullet being stuck in the bore when extracting a live round from the chamber). Many early Winchester rifles have had their throats lengthened to allow more conventional bullet seating, though handloading for rifles produced by other manufacturers has revealed notable differences in throat length.
The .264 Winchester Magnum thrives on slow-burning powders, such as all 4350s, IMR and Hodgdon 4831, H-1000 and others with a similar burn rate.
With its over-bore capacity, it performs notably better when fired from a 26-inch (or longer) barrel. The test rifle used here featured a 24-inch barrel, so velocities fell short when compared to longer versions. Depending on load, expect a 30- to 60-fps velocity increase per inch of barrel.