By: Patrick Burell
Rimfire: "A term used to describe a method of ignition for metallic firearm cartridges as well as the cartridges themselves. It is called rimfire because the firing pin of a gun strikes and crushes the base's rim to ignite the primer. This is in contrast to the more common centerfire method, where the firing pin strikes the primer cap at the center of the base of the cartridge."
Figure 1: Pellet, CB cap, CB Short, cb long,.22 Short, .22 Long, .22 LR, .22 Automatic, .22 WRF, .22 WRM (22 Mag)
Think back to a time when differences were settled with a cap and ball pistol. In 1831, as the industrial revolution was coming to a close the first all metallic cartridge made its way into the firearms world known as the Rimfire Cartridge.
What makes a rimfire cartridge so different? The primer is spun in the rim and sides of the brass casing where the firing pin actually strikes the rim at the rear of the cartridge. First developed in the early 1830's it wasn't until 1845 when famous French gun maker Nicolus Flobert developed a practical cartridge the .22 Flobert or CB. Then came along Smith & Wesson.
If it wasn't for Smith & Wesson no telling which direction this little cartridge would have ended up. As the .22 was being developed Smith & Wesson was developing their first revolver. So, in 1857, Smith & Wesson debuted their first revolver in a new .22 cartridge, the .22 short.
Who would have known that Smith & Wesson's .22 short would lead the rimfire movement. The .22 short led to the .22 long, in 1871, having the same bullet weight but being backed by a longer case and more powder. The .22 long led to the defunct .22 Extra-long, having a longer case and heavier bullet. But, because the extra-long fouled the barrel rather quickly it fell by the wayside. The .22 long also gave birth to the .22 long rifle in 1887. With its case being the same length and having the same bullet as the Extra-long it made for a nice rifle round. Ultimately leading to the .22 Magnum developed by Winchester in 1959. But, the .22 was not the only rimfire developed.
As the dark years of the American Civil War fell upon the United States the .22 led to larger calibers in the rimfire configuration. These larger calibers included .30 rimfire, .32 rimfire, .38 rimfire, .41 short, .44 Henry Flat and the .58 miller. These larger calibers did not last long as they were quickly replaced with centerfire cartridges.
While the larger rimfires fell by the wayside the .22 ruled the rimfire scene for over a century until Hornady introduced their new .17 rimfire cartridges. Hornady introduced the .17 HMR in 2002 and the .17 HM2 it’s to early to tell if the .17 is going to be as popular as the .22 but I have a feeling that it will be. The .22 rimfire is the oldest and longest produced cartridge in the world. We all own one and most likely began our live fire shooting with one.