.22 Long Rifle
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The .22 Long Rifle rimfire cartridge is a long established variety of ammunition, and in terms of units sold is still by far the most common in the world today. The cartridge is often referred to simply as a ".22 LR" and various rifles, pistols, revolvers, and even some smoothbore shotguns have been manufactured in this caliber. For many decades, it has been the most popular cartridge in the world. Virtually every manufacturer of cartridge firearms makes at least one model chambering it, and this has been true for more than a century. The .22 Long Rifle and related cartridges use a heeled bullet, which means that the bullet is the same diameter of the case, and has a narrower "heel" portion that fits in the case.
The low cost, minimal recoil, and low noise make the .22 LR an ideal cartridge for plinking, and it is often purchased in bulk. The standard box of .22 LR contains 50 rounds, and .22 LR is often sold by the brick, containing 10 boxes for 500 rounds, or the case containing 10 bricks for 5000 rounds.
.22 LR ammunition is available in a very wide variety, and a very wide price range. Bullet weights range from 30 to 60 grains (1.9 to 3.9 g), velocities from 350 to 1750 feet per second (110 to 530 m/s). "Promotional" loads for plinking can be found for under US$10.00 per brick, while precision target rounds can cost US$80.00 per brick. Currently, a standard box of 50 rounds goes for $1.00 US.
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Performance
The .22 LR is inexpensive, often costing less than two US cents per cartridge. It is effective within 150 meters (490 ft) (after 150 meters the ballistics of the round are such that the large "drop" will be difficult to compensate). The relatively short effective range, low report, and light recoil has made it a favourite for use as a target practice cartridge. The accuracy of the cartridge is good, but not exceptional; various cartridges are capable of the same or better accuracy. Still, the effectiveness of this cartridge is often underestimated. The trajectory of the .22 LR "has a 2.7 inch rise at 50 yards and 10.8 inch drop at 150 yards when zeroed at 100 yards." [1] "Practically speaking, a .22 LR rifle needs to be zeroed at about 75 yards to avoid over-shooting small animals like squirrels at intermediate distances." [2]
The newest commercial rimfire, the .17 Mach 2, is based on the .22 LR case, but is slightly stretched in length and necked down. The light, aerodynamic .17 caliber (4.5 mm) bullet gives a much higher velocity than the .22 LR at the expense of a price of several times that of the .22 LR, and of an increased noise of firing caused by the higher muzzle pressure and supersonic bullet.
As a hunting cartridge, the .22 LR is mainly used to kill small varmints such as rats and squirrels. It is also effective on rabbits over distances closer than 125 meters and on ground hogs closer than 75 meters. For greater range or larger game, a more powerful cartridge should be used to ensure a clean kill. Examples include larger rimfire rounds such as the .22 WMR, .17 HMR, or any centrefire cartridge. Like any bullet, the .22 LR is nonetheless dangerous and capable of killing humans and large animals.
Variants
There are a variety of different types of .22 Long Rifle (or ".22 LR") loads. They are sometimes divided into 3 categories; subsonic, standard and hyper-velocity (or ultra-velocity).
Subsonic rounds have a muzzle velocity of 330 m/s or less and are often equipped with an extra heavy, 2.9-3.9 gram bullet. As the speed of sound in air at 20 °C (68 °F) is approximately 343.4 m/s (1126 ft/s), the subsonic round's muzzle velocity is very close to the speed of sound under many hunting conditions, and only very slightly below it. However, under cold air conditions at 0 °C (32 °F), the speed of sound drops to 331.5 m/s (1087.6 ft/s), essentially the same speed as the muzzle velocity of the subsonic round. Hence, a so-called subsonic round when used under slightly colder conditions than 0 °C (32 °F) is usually no longer subsonic. This may be an important point to remember for successfully making follow-up shots on multiple targets when winter hunting with subsonic rounds.
Standard rounds have a supersonic muzzle velocity and a "normal" weight, 2.5 to 2.6 gram bullet.
So-called hyper-velocity bullets may have a muzzle velocity of 450 to 550 m/s and this velocity is partially due to the light bullets they use. The bullets are usually around 1.9-2.2 grams in weight. The bullets themselves are in all cases usually either solid or hollow-point bullets.
Special shot cartridges, usually loaded with #12 shot (see shotgun shell) in this caliber have been made and these are ideal for pest control at very short ranges. Such rounds will either have a longer brass case that is crimped closed, or a translucent plastic "bullet" that contains the shot and shatters upon firing. In a specially made .22 bore shotgun, the shotshells can be used for short range skeet shooting and trap shooting at special, scaled down clay targets.
.22 LR High Velocity
.22 LR High Velocity cartridges use a larger, slower burning powder charge to generate supersonic velocities. These rounds generally show less of an improvement in handguns, where the short barrel does not take full advantage of the slower powder. The downside to high velocity rounds is that the bullet often drops to subsonic speeds on the way to the target, which can degrade accuracy. The extra power and penetration, however, more than make up for the slight loss in accuracy for applications such as small game hunting.
Many .22 LR cartridges use bullets lighter than the standard 40 grains (2.6 g), fired at even higher velocities. The CCI Stinger was the first "hyper velocity" .22 LR cartridge, and provides a very large increase in velocity over standard .22 LR rounds. The Stinger uses a longer case, a stronger charge and copper plating on a lighter bullet. The case is longer than that of the normal Long Rifle cartridge, yet Stingers will fit in most Long Rifle firearms. The powder is designed to burn more slowly and thus make the most use of the length of a rifle barrel. In the Stinger the extra case length is compensated by a shorter bullet, which is only available as a jacketed hollow point. The thin copper layer on the bullet functions as a lubricant and reduces the friction between the high velocity bullet and the barrel, thus reducing barrel wear. It also has an oxidation-preventing effect on the lead bullet. Lead tends to oxidise if stored over long periods of time and as a result of this, the bullet's diameter increases to a level that might both prevent the insertion of the cartridge in the chamber and might cause the pressure in the barrel to rise to a dangerously high level. The increase in pressure may lead to the case rupturing and potential danger to the shooter. Standard and subsonic cartridges tend to use a type of wax for the same purpose.
Usage
Today .22 Long Rifle ammunition is mainly being used for hunting small pests, for sports shooting and for cheap training. .22 LR is the choice for several ISSF shooting events: 50 m Rifle, 50 m Pistol, 25 m Pistol, 25 m Rapid Fire Pistol and 25 m Standard Pistol, plus divisions of metallic silhouette and pin shooting, most high school, collegiate, Boy Scouts of America, and 4H shooting events, and many others. With high quality ammunition, the .22 Long Rifle can be quite accurate. Its main advantages are low cost, low recoil and low noise. Its main disadvantage is its low power; it is only suitable for small game, and as a defensive cartridge it is considered very underpowered, though the small size allows very lightweight, easily concealable handguns which can be carried in circumstances where anything larger would be impractical.
The tiny case of the .22 Long Rifle, and the subsonic velocities (when using subsonic ammunition) make it well suited for use with a suppressor. The low volume of powder gasses mean that .22 suppressors are often no larger than a bull barrel; the Ruger 10/22 and Ruger MK II are common choices, due to their reliability and low cost, and the resulting product is often nearly indistinguishable from a bull barrel model (although weighing far less). Where suppressors are only minimally restricted, a .22 Long Rifle with a suppressor is often a favored firearm for plinking, as it does not require hearing protection or disturb the neighbors.
Suppressed .22 caliber pistols are often found in the arsenals of special forces, intelligence agencies, and organized crime organizations. For example, the 22 LR Ruger MK II has seen extensive use in the arsenal of the US Navy Seals. Likewise, Gary Powers was issued a suppressed High Standard pistol for the flight in which he was shot down. The .22 LR has also been found to be the weapon of choice for several suspected Mafia assassinations, with the victim usually being shot at close range in the head, the damage being such that the round has enough momentum and penetrating power to enter the skull but not to exit. Such inexpensive Saturday night special pistols used in this way are called doctor guns, the implication being that they are most effective when inserted into an orifice (such as a nostril, or ear) before being fired, and then being disposable by virtue of their very low cost. The notion of the .22 LR as a mob weapon has steadily begun to enter into American pop culture in recent years, being featured in the movie Assassins and in the television series The Sopranos. Even without a suppressor, a .22 Long Rifle pistol is far quieter than any but the smallest centerfire cartridges. With a suppressor, there is a long history of its use in intelligence agencies dating to World War II by the pre-cursor to the CIA, the OSS.
Specifications
Standard dimensions are as follows:
- Case length: 15 mm (0.595 in )
- Case diameter: 5.71 mm (.225 in)
- Bullet diameter: 5.68 mm (.224 in)
- Rim diameter: 6.88 mm (.271 in)
- Rim thickness: 1 mm (.040 in)
- Cartridge overall length: 25 mm .985 in
- Muzzle velocity (nominal):
- 40 gr (2.6 g) lead: 1082 ft/s (330 m/s) .22 LR (subsonic)
- 36 gr (2.33 g) copper plated lead: 1328 ft/s (405 m/s) .22 LR High Velocity
Note: actual velocities are dependent on many factors, such as barrel length of a given firearm and manufacturer of a given lot of ammunition, and will vary widely in practice. The above velocities are typical.
Compatible ammunition
The .22 Long rifle uses a straight walled case. Depending upon the type and the feed mechanism employed, a firearm which is chambered for .22 Long Rifle may also be able to safely chamber and fire the following shorter rimfire cartridges:
The .22 Winchester Magnum Rimfire, also called .22 Magnum or .22 WMR, uses a different case, which has a significant taper and does not use a heeled bullet. Firing a .22 Long Rifle or derivative in a .22 WMR firearm will likely result in a potentially dangerous case rupture.
See also
- 5 mm caliber
- Silencer (Especially the sub-section on History, mentioning William Donovan demonstrating a silenced .22 to President Roosevelt)