The .220 Swift
Date: Jun 15 2008
The fortunes of the .220 Swift have gone up and down over the decades. Introduced by Winchester in 1935, just in time for the last year of its Model 54 bolt-action rifle and the introduction of the Model 70 a year later, it was the first factory cartridge to obtain over 4,000 fps at the muzzle and proved to be tremendous varmint cartridge.
Early Problems With The 220 Swift
But the .220 also had its problems. The barrel steels of the day eroded easily at the high throat temperatures created by lots of hot gas being forced through a rather small hole. Plus, when handloaders tried their hands with the era’s popular powders, they found the Swift a little touchy at top pressures. A lot of shooters also felt compelled to try the Swift on big game. With the typical varmint bullets of the day, sometimes this worked and sometimes it didn’t.
All these problems were solved by better barrel steels, better powder, and better bullets. Yet the early reputation of the Swift was so damaged that Winchester dropped the chambering when it redesigned the Model 70 in 1964. Five years later Remington brought out the old .22-250 wildcat as a factory cartridge with great success, and the .220 Swift almost disappeared completely.
The 220 Swift Revival
However, in the 1980s it started making a comeback, perhaps not so coincidentally about the time chronographs became cheap enough for average handloaders. Speed became paramount, and the Swift always was about 100 fps faster than the .22-250. Handloaders started using the round again, and factories chambered for it. The problems of the old days were mostly gone, but soon a new generation found the Swift wasn’t perfect in other ways.
For some reason, Winchester decided to rather loosely base the Swift on the 6mm Lee Navy cartridge, which had a base diameter of .445 inch and a rim diameter of .448 inch. But to work correctly in Model 54s and Model 70s without any extensive modifications to the rifles themselves, the .220 Swift was given a rim diameter of .473 inch, the same as the .30-06 and its various descendants.
This means the .220 Swift is technically “semi-rimmed,” with a rim diameter larger than the base of the cartridge. Generally, this doesn’t cause any problems, but in some bolt actions, feeding problems can result if care isn’t taken when loading the rounds into a box magazine.