History of Rimfire Ammunition
By Sam Jacobs
The original concept for rimfire ammunition was seen in 1831 in a patent which, like the rimfire cartridges of today, also used a thin case. This design eventually became the Flobert .22 BB Cap by 1845. This ammunition cartridge housed the priming compound just inside of the rim. The original velocities were very low, even being compared to the strength of an airgun.
Then the .22 Short was introduced in 1857, which used a longer rimfire case and 4 grains of black gunpowder. This cartridge was to be used by Smith & Wesson for their first revolver. Eventually, the cartridge became the 22 Long we know today – one of the most commonly used cartridges in the world (not to be mistaken with the 22 LR cartridge though). Today the .22 caliber rimfire ammunition represents the last remnants of the original rimfires.
Rimfire ammunition is a type of firearm cartridge in which the firing pin strikes the rim of the base, instead of the primer cap at the base center (otherwise known as a centerfire cartridge). The rimfire cartridge rim is simply a lengthened and widened percussion cap that houses priming compound. The cartridge case contains the gun powder and the bullet. Rimfire ammunition cartridges are not reloaded after the first firing, since the head is damaged by the firing pin impact. While a variety of priming methods have been theorized, only the rimfire and centerfire priming methods are commonly used.
Rimfire ammunition can only be utilized in calibers that produce low pressure, as they need a thin case for the primer to be ignited by the firing pin. Therefore, present-day rimfire cartridges are generally .22 caliber or less. These low pressures make it possible for guns that use rimfire ammunition to be very affordable and lightweight, which contributes to the consistently rising popularity of the lower caliber rimfire ammunition presently being sold around the world.
Rimfire ammunition is extremely valued by cartridge collectors worldwide, who base the worth of rimfire ammunition on how rare the headstamp is. A sub-industry of collectible rimfire ammunition exists in which cartridges with special headstamps are sold to commemorate individuals that have made significant contributions to the rimfire industry. Generally, these rare cartridges are issued in small amounts when the famous individual retires or dies. Frequently, these collector’s cartridges are given to the retiring individual themselves (or their families), providing them the opportunity to choose how the cartridges are sold.