The .284 Winchester was introduced in 1963, designed specifically for the Winchester Model 88 lever action and Model 100 100 auto-loading rifles. It was intended to produce similar ballistics to the .270 Winchester and .280 Remington, but with an overall cartridge length more or less equal to the .308 Winchester, which allowed it to function in short-action rifles. The case was new and not based on any pre-existing case or cartridge. The rim was rebated (reportedly to function better in the rifles noted above) and had the same .473-inch diameter as the .30-06 case. The case was comparatively fat, measuring .500 inch in head diameter, which helped to increase powder capacity. The shoulder angle, 35 degrees, was comparatively steep. Maximum average pressure was established at 54,000 CUP, or nearly 64,000 psi using today’s pressure testing methods. It was truly a modern design that was clearly ahead of its time.

In addition to the above mentioned Winchester rifles, the cartridge was chambered (in very limited quantities) by Ruger in its M77, Savage in its Model 99 and by other rifle companies Thompson/Center. Unfortunately, its popularity was limited due primarily to being chambered in two Winchester rifles that were headed toward discontinuance; neither did they offer the same level of accuracy and reliability of bolt-action rifles. The .284 Winchester nonetheless an excellent cartridge that deserved to become more popular. It is noteworthy that it has enjoyed some success in long-range competitions.

The .284 is the parent cartridge for the 6.5-284 Norma as well as the .450 Bushmaster and .475 Wildey Magnum. It has also been the bases for several wildcats, including the 6mm-284, .284 Shehane, .30-284, .338-284, .35-284, .375-284 and others.

The accompanying data was developed using Sierra bullets fired in a 26-inch Match Grade Machine test barrel. A few examples of the ballistics obtained included the Sierra 100-SPT bullet, select powders reached 3,000 fps and even approached 3,100 fps, while several powders pushed 150-grain bullets between 2,800 to 2,900 fps, all of which is impressive performance from a short-action cartridge with a modest capacity. Incidentally, similar to modern short magnum and short bench rest cartridges, the .284 Winchester exhibited low extreme velocity spreads and outstanding accuracy.

To view the accompanying data, CLICK HERE.