In relation to rifles and rifle shooting, when someone mentions the term "22", what they are most likely referring to is the .22 Long Rifle. It is probably the most popular rifle cartridge produced today. Even though it is a rimfire cartridge and lacks the same amount of power as its centerfire big sisters, it does have a place in the shooting sports and hunting fields.
In the greater scheme of things, the .22 Long Rifle was the third attempt at a .22 caliber rimfire cartridge, coming after the .22 Short and the .22 Long, respectively. Third time's a charm, because this was the one rimfire cartridge that took the world by storm. And why shouldn't it? It is inexpensive to produce, cheap to purchase and is easy to shoot. They come in boxes of 50 each, 10 boxes to a "brick", 5,000 rounds to a case. They have names like "Thunderbolt", "Yellow Jacket", and "Velociter". Depending on quality, prices are usually about $10-20 per brick, and occasionally more. One of the more popular rifles chambered in this caliber is the Ruger 10/22 and as a sign of its popularity, it has many aftermarket accessories, such as extended magazines.
The .22 Long Rifle was developed thirty years after the .22 Short, around 1887 or so. Overshadowing its little brothers (nearly 1 inch long), the .22 Short and the .22 Long, the .22 Long Rifle was longer than either and had more power than both. Good for shots up to 100 yards (though, most people keep shots within 50 yards), it works its magic on both targets and game alike. Eventually, it was dwarfed in power by the .22 Winchester Magnum Rimfire, though it remains the most popular of the rimfire cartridges.
The .22 Long Rifle is used for:
- Target shooting: this can be anything from informal matches you have with friends at your local gun club, to the caliber of the Olympic trials and other formal matches.
- A .22 is quite deadly on small game, such as rabbit, squirrel, crow, pigeon and groundhog (woodchuck). It is thought of as a pest control tool, in addition to bring meat home for the pot.
- Plinking: Plinking is a form of shooting that isn't formal target practice, but it isn't exactly goofing off, either. It is best described as recreational shooting. Shooting at walnuts, apples, tin cans and so forth is considered plinking.
- As there is nearly no recoil, anyone can shoot the .22 with little trouble and learn how to develop proper marksmanship skills. Many young girls and boys learn to shoot with this cartridge, as early as 8 years old. Chances are that if you have shot a rifle, you have shot a .22.
The weight of the .223" caliber slug varies depending on the load and purpose, but the typical .22 is 40 grains in weight and has an average velocity of 1250 feet per second (one must understand that there is variation, shell to shell, lot to lot, of any kind of ammunition). Different types of bullets and different uses dictate the weight and speed of the cartridge.
Every major ammunition manufacturer makes a .22 Long Rifle cartridge. Winchester, Federal, Remington, Eley and CCI all have a healthy catalog of different types of .22 cartridges. Subsonic rounds, hollow points, and rat shot shells are available.
The .22 Long Rifle can only be used in firearms marked appropriately. .22 Short and .22 Long shells can be used in a rifle marked for the .22 Long Rifle. However, the converse is not true. Today, a .22 rimfire rifle is marked "Will accept .22 Short, Long and Long Rifle".
Sources:
http://www.winchester.com/
http://www.remington.com/
http://www.cci-ammunition.com/
http://www.rimfirecentral.com