Way back in 19 and 58, Winchester introduced a new cartridge called the .284 (which was its bore diameter) designed to bring .270-style ballistics to its hideously inaccurate Model 100 autoloader and its handsome, but nearly as inaccurate, Model 88 lever action. The round was a commercial failure, but it was a remarkable design, and while the public yawned at the .284, wildcatters went mad with joy and necked the thing up, down, and sideways.
The cartridge is .308-length, but has a magnum-diameter body, a .30/06-sized rim, a very sharp (35-degree) shoulder, and a short neck. It’s a very efficient package, and over the years we have seen wildcats in 6mm/284 (I shot one back in 1968) 6.5/284, .270/284 and on to .35/284. Of these, the 6.5/284 is the most successful, and in recent years has gotten a great deal of attention from Highpower target shooters. There are two reasons: 6.5mm bullets in 140-grain (and higher) weights are extremely long for their caliber. Their high ballistic coefficients and sectional densities allow them to buck the wind fairly well and hold their velocity very well.
Moreover, the .284 case holds enough powder to move these slugs at around 3,000 fps, but not at the price of high recoil. The fact is that the 6.5/284 is a notably light-kicking cartridge. But because the .284 was such a poor seller, Winchester produced very little ammo in this caliber. Brass was hard to come by, and what there was, I am told by wildcatters, was of poor quality. However, better days were ahead.