Winchester introduced the .243 Winchester in 1955 for its Model 70 bolt-action and Model 88 lever-action rifles. Savage quickly adopted it for its Model 99 lever- and Model 110 bolt-action rifles. The .243 (6mm) Winchester is simply the .308 Winchester case necked down. Original development and publicity was due largely to one gun writer, the late Warren Page, who, along with other wildcatters, worked out a similar version before Winchester. The .243 is probably chambered in more different rifles than any other cartridge, except possibly the .30-06 Springfield. All other manufacturers of rifles offer this caliber. The .243 Winchester represents a successful effort to develop a light deer rifle caliber that could hold its own with the high-velocity .22s for long-range use on small targets and still be adequate for larger animals. The .243 does this job well. It eliminates the need to own two different rifles for anything from small game and pests up to and including deer and antelope. The 80-grain bullet is intended primarily for varmint and small game and the 100-grain bullet for deer-size animals. All major domestic and overseas manufacturers of commercial ammunition offer this caliber. Its popularity as a deer caliber has prevailed over its varmint capabilities.
Editor's Note: This brief is an excerpt from Cartridges of the World 14th Edition.