Rimfire Ammunition - History

History

The idea of placing a priming compound in the rim of the cartridge evolved from an 1831 patent, which called for a thin case, coated all along the inside with priming compound.

By 1845, this had evolved into the Flobert .22 BB Cap, which distributed the priming compound just inside the rim. The .22 BB Cap is essentially just a percussion cap with a round ball pressed in the front, and a rim to hold it securely in the chamber. Intended for use in an indoor "gallery" target rifle, it used no gunpowder, but relied entirely on the priming compound for propulsion. Velocities were very low, comparable to an airgun. The next rimfire cartridge was the .22 Short, developed for Smith and Wesson's first revolver, in 1857; it used a longer rimfire case and 4 grains (260 mg) of black powder to fire a conical bullet.

This led to the .22 Long, same bullet weight as the short, but with a longer case and 5 grains (320 mg) of black powder. This was followed by the .22 Extra Long with a case longer than the .22 Long and a heavier bullet. The .22 Long Rifle is a .22 Long case loaded with the heavier Extra Long bullet intended for better performance in the long barrel of a rifle. The .22 Long Rifle is the most common cartridge in the world. Larger rimfire calibers were used during the Civil War in the Henry Repeater and the Spencer Repeater. While larger rimfire calibers were made, such as the, .30 rimfire, .32 rimfire, .38 rimfire .41 Rimfire Short, the .44 Henry Flat devised for the famous Winchester 1866 carbine, up to the .58 Miller, the larger calibers were quickly replaced by centerfire versions, and today the .22 caliber rimfires are all that survive of the early rimfires.

The early 21st century has seen a revival in interest in rimfire cartridges, with two new rimfires introduced, both in .17 caliber (4.5 mm).

Below is a list of the most common current production rimfire ammunition:

• The powderless .22 Cap rounds, including BB Cap.
• .22 Short, used for target shooting and Olympic and ISSF 25 m Rapid Fire Pistol competition until 2005
• .22 Long (obsolete)
• .22 Long Rifle (.22 LR), the most common cartridge made
• .22 Long Rifle High Velocity Mini-Mag (.22 LR)
• .22 Stinger (slightly longer case, same overall loaded length) - the basis for the .17 HM2
• .22 Winchester Rimfire (.22 WRF) AKA .22 Remington Special (obsolete)
• .22 Winchester Magnum Rimfire (.22 WMR)
• .17 Hornady Magnum Rimfire (.17 HMR), a .17 caliber based on the .22 WMR case
• .17 Hornady Mach 2 (.17 HM2), a .17 caliber based on the .22 Stinger case
• 5 mm Remington Rimfire Magnum (recently put back into production by Aguila Ammunition/Centurion)

A new and increasingly popular rimfire, the 17 HMR is basically a .22 WMR with a smaller formed neck which accepts a .17 bullet. The advantages of the 17 HMR over .22 WMR and other rimfires are its much flatter trajectory, and its highly frangible hollow point bullets (often with plastic "ballistic tips" that improve the external ballistics performance). The .17 HM2 is based on the .22 Long Rifle and offers similar performance advantages over its parent cartridge, at a significantly higher cost. While .17 HM2 sells for about four times the cost of .22 Long Rifle ammunition (per box of 50 rounds), it is still significantly cheaper than most centerfire ammunition, and somewhat cheaper than the .17 HMR.

A notable rimfire still in production in Europe, and chambered by the Winchester Model 39 in the 1920s, is the 9 mm Flobert. This cartridge can fire a small ball, but is primarily loaded with a small amount of shot, and used in smoothbore guns as a miniature shotgun, or "garden gun". Power and range are very limited, making it suitable only for pest control. An example of rare but modern 9 mm Flobert Rimfire among hunters in Europe is the 1.75" Brass Shotshell manufactured by Fiocchi in Lecco, Italy using a .25 oz shot of #8 shot with a velocity of 600 fps.