. 22 Long Rifle The . 22 Long Rifle rimfire ( 5 . 6×15R – metric designation ) 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 . 22 LR ( " " twenty - two - - " " ) and various rifles , pistol s , revolver s , and even some smoothbore shotgun s have been manufactured in this caliber . The cartridge originated from the Flobert BB Cap of 1845 through the . 22 Smith & Wesson cartridge of 1857 , and was developed by the American firearms manufacturer J . Stevens Arms & Tool Company in 1887 by combining the casing of the . 22 Long with the bullet of the . 22 Extra Long . For many decades , it has been a very popular cartridge around the world . It is one of the few cartridges that are accepted by a large variety of rifles , as well as pistols . The . 22 Long Rifle and related cartridges ( . 22 Short , . 22 Long and . 22 Extra Long ) use a heeled bullet , which means that the bullet is the same diameter as the case , and has a narrower " heel " portion that fits in the case . Popularity . Low cost , minimal recoil , and relatively low noise make . 22 LR an ideal cartridge for recreational shooting , initial firearms training , small - game hunting and pest control . Used by Boy Scouts for the rifle shooting merit badge , . 22 LR is popular among novice shooters and experts alike . The rimfire round is commonly packaged in boxes of 50 or 100 rounds , and is often sold by the " brick " , a carton containing either 10 boxes of 50 rounds or loose cartridges totaling 500 rounds , or the " case " containing 10 bricks totaling 5 , 000 rounds . A wide variety of rimfire ammunition is available commercially , and the available ammunition varies widely both in price and performance . Bullet weights among commercially available ammunition range from , and velocities vary from . Promotional loads for plinking can be purchased in bulk for significantly less cost than precision target rounds . The low cost of ammunition has a substantial effect on the popularity of . 22 LR . For this reason , rimfire cartridges are commonly used for target practice . The low recoil of the cartridge makes it ideal for introductory firearms courses . Novice shooters can be surprised or frightened by the recoil of more powerful rounds . Beginners shooting firearms beyond their comfort level frequently develop a habit of flinching in an attempt to counter anticipated recoil . The resulting habit impedes correct posture and follow - through at the most critical phase of the shot and is difficult to correct . With high recoil eliminated , other errors in marksmanship technique are easier to identify and correct . AR - 15 upper receivers and M1911 slide assemblies are available for this round . CZ Model 75 handguns also have a fixed barrel upper pistol conversion kit to make it shoot . 22 ammunition . These rimfire conversions allow shooters to practice inexpensively while retaining the handling characteristics of their chosen firearms ( with reduced recoil and muzzle blast ) . Additionally , . 22 conversion kits allow practice at indoor ranges which prohibit high - power rifles . The ' fun factor ' of shooting a high powered pistol converted to low energy . 22 rounds is cited among the reasons for the conversion kits , in addition to lower ammunition costs . Owners of guns that use gas systems , such as AR - 15 sport style rifles , normally avoid firing non - jacketed . 22LR ammunition , as the use of unjacketed ammunition may lead to fouling of the gas port inside the barrel and costly gunsmithing procedures . Annual production is estimated at 2 – 2 . 5 billion rounds . Performance . Performance varies between barrel length and the type of action . For example , bolt action rifles may perform differently than semi - automatic rifles . . 22 LR is effective to , though practical range tends to be less . After 150 yards the ballistics of the round are such that it will be difficult to compensate for the large " drop " . The relatively short effective range , low report , and light recoil has made it a favorite 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 . A contributing factor in rifles is the transition of even a high - velocity cartridge projectile from supersonic to subsonic within . As the bullet slows , the shock wave caused by supersonic travel overtakes the bullet and can disrupt its flight path , causing minor but measurable inaccuracy . When zeroed for , the arc - trajectory of the standard high - velocity . 22 LR with a bullet has a rise at , and drop at . A . 22 LR rifle needs to be zeroed for to avoid over - shooting small animals like squirrels at intermediate distances . As a hunting cartridge , rimfire are mainly used to kill small game . It is highly effective on squirrels and rabbits at distances closer than and on ground hogs , marmots , and foxes closer than . It has been successfully used on large creatures such as coyotes , but range should be limited to no farther than ; head and chest shots are mandatory with the most powerful . 22 cartridge the hunter can use accurately . A standard rimfire cartridge can have a ballistic range of up to . Because a . 22 LR bullet is less powerful than larger cartridges , its danger to humans is often underestimated . In fact , a . 22 LR bullet is capable of inflicting very serious injuries ( e . g . the four people wounded during the Reagan assassination attempt ) or death e . g . the Kauhajoki school shooting ( 11 killed and 1 wounded ) , the Jokela school shooting ( 8 killed and 1 wounded ) , or the 1979 Cleveland Elementary School shooting ( 2 killed and 8 wounded ) as well as the assassination of Robert F . Kennedy . Numerous other shooting incidents have demonstrated that . 22 LR bullets can easily kill or seriously injure humans . Even after flying , a . 22 bullet is still traveling at approximately . Ricochets are more common in . 22 LR projectiles than for more powerful cartridges as the combination of unjacketed lead and moderate velocities allows the projectile to deflect – not penetrate or disintegrate – when hitting hard objects at a glancing angle . A . 22LR can ricochet off the surface of water at a low angle of aim . Severe injury may result to a person or object in the line of fire on the opposite shore , several hundred yards away . Rimfire bullets are generally either plain lead ( for standard velocity loads ) or plated with copper or gilding metal ( for high velocity or hyper velocity loads ) . The thin copper layer on the bullet functions as a high velocity lubricant reducing friction between the bullet and the barrel , thus reducing barrel wear . It also prevents oxidation of the lead bullet . Lead tends to oxidize if stored for long periods . Oxide on the bullet ' s surface could increase its diameter enough to either prevent insertion of the cartridge into the chamber , or – with hyper velocity rounds – cause dangerously high pressures in the barrel , potentially rupturing the cartridge case and injuring the shooter . Standard and subsonic cartridges use a wax lubricant on lead bullets for the same purpose at lower velocities . Variants . There are a variety of . 22 LR loads . They are often divided into four distinct categories , based on nominal velocity : Subsonic . Subsonic rounds have a muzzle velocity of approximately , less than the speed of sound . These rounds are sometimes equipped with extra heavy bullets of to improve the terminal ballistics of the slower projectile . Conversely , these rounds may contain little more than a primer and an extra - light bullet . Subsonic rounds are favored by some shooters due to slightly superior accuracy and reduction in noise . Supersonic rounds produce a loud crack which can scare away animals when hunting . Accuracy is reportedly improved with subsonic rounds because a supersonic bullet ( or projectile ) that slows from supersonic to subsonic speed undergoes drastic aerodynamic changes in this transonic zone that might adversely affect the stability and accuracy of the bullet . Additionally , the use of subsonic rounds is reported to reduce wastage of meat caused by a high - velocity round passing and destroying tissue . Because the speed of sound in air at is approximately , the subsonic round ' s muzzle velocity is slightly below the speed of sound under many hunting conditions . However , under cold air conditions at , the speed of sound drops to , approximately muzzle velocity . Hence , a " subsonic " round used below this temperature may be supersonic , and during the transition from supersonic to subsonic velocity , it may become unstable , reducing accuracy . To counteract this , some cartridge manufacturers have lowered the speed of their subsonic ammunition to or less . Various combinations of subsonic rounds and semi - automatic . 22 LR firearms result in unreliable cycling of the firearms ' action , as the result of insufficient recoil energy . Some subsonic rounds use heavier bullets ( achieving lower velocities ) in order to ensure that , as a result of increased bullet mass , there is enough energy to cycle common blow - back actions . As an example , the Aguila . 22 LR SSS " Sniper SubSonic " round , has a bullet on . 22 Short case , providing the cartridge the same overall dimensions as a . 22 Long Rifle round . However , other problems may be encountered : the heavier and longer bullet of the Aguila cartridge requires a tighter barrel twist ( by the Greenhill formula ) to ensure that the bullet remains stable in flight . There are two performance classes of . 22 rimfire subsonic rounds . Some subsonic rounds , such as various . 22 Short or . 22 Long " CB " rounds , give ~ velocity with a bullet providing relatively low impact energy . These may not use any , or only small amounts of gunpowder , and have the characteristics of rounds intended only for indoor training or target practice rather than hunting . Where these are in . 22 LR form , it is only to aid feeding in firearms designed for the cartridge , rather than older . 22 CB shooting gallery rifles . The Aguila SSS gives ~ velocity with a bullet offering energy equivalent to many high velocity . 22 Long Rifle rounds using standard bullets . Other heavy bullet subsonic rounds give similar performance , and are intended for hunting of small game , or control of dangerous animals , while avoiding excessive noise . Standard velocity . Standard velocity rounds have a slightly supersonic muzzle velocity of around , and a " normal " bullet weight of . Standard velocity cartridges generate near or slightly - supersonic velocities . These rounds generally do not develop these velocities in handgun s because the short barrel does not take full advantage of the slower powder . High velocity . The Long Rifle was originally loaded with black powder . The first smokeless powder loads were intended to match the standard velocity of the original black powder rounds . Smokeless powder is more efficient than black powder , and the cartridge cases could hold more powder . Smokeless powder loads , called " high speed " or " high velocity " , were offered by the major ammunition makers , giving a typical velocity increase of twenty percent ( to ) while still using the standard solid or hollow point lead bullet . Hyper velocity . Many . 22 LR cartridges use bullets lighter than the standard , fired at even higher velocities . " Hyper velocity " bullets usually weigh around to and can have a muzzle velocity of to . This higher velocity is partially due to the use of lighter bullets . The CCI Stinger was the first hyper velocity . 22 LR cartridge , and provided a significant increase in velocity and energy over standard rimfire rounds . The Stinger case is longer than that of the Long Rifle ( approx . versus for the Long Rifle ) but the plated hollow point bullet is lighter and shorter at , giving the same overall length as the Long Rifle cartridge . A powder with a slower burning rate is used to make the most use of the length of a rifle barrel . Most . 22 Long Rifle powders increase velocity up to about of barrel length ; the powder used in the Stinger increases velocity up to the longest . 22 barrel length tested by the NRA , . Later hyper velocity rounds were introduced by other makers , based on the Long Rifle case with lighter bullets in the weight range and slow burning rifle powder loadings . The overall length of many of these cartridges was less than the standard overall length of the standard Long Rifle . One example was the Remington Viper , another is the Federal Spitfire . The CCI Velocitor hyper velocity round uses the standard Long Rifle case size and a standard weight bullet of proprietary hollow point design to augment expansion and trauma . This cartridge has a muzzle velocity of . Due to the better ratio of bullet mass to air resistance , Velocitor performs better at longer range compared to the light bullets of other hyper velocity rounds . Shot cartridges . Special . 22 LR caliber shot cartridges , usually loaded with # 12 shot , have also been made . These are often called " rat - shot " or " snake - shot " due to their use in very short range pest control . Such rounds have either a longer brass case that is crimped closed , or a translucent plastic " bullet " that contains the shot and shatters upon firing . In specially - made . 22 bore shotgun s , the shot shells can be used for short range skeet shooting and trap shooting at special , scaled - down , clay targets . Full metal jacket . During World War II , a full metal jacketed version of the . 22 LR was developed for the suppressed High Standard HDM pistol . Tracer . Tracer ammunition is also available in rimfire . Cartridge construction . The standard . 22 rimfire cartridges ( BB , CB , short , long , long rifle ) differ in construction from most other cartridges in the way the bullet is constructed and held in the case . In " normal " cartridges , the bullet is inserted completely within the " neck " of the cartridge case , being held in place by tension from the case neck around the bullet bearing surface and , in some cases , a small crimp at the very top of the case around a cannelure ( groove ) in the bullet . Bullets for the standard . 22 RF ( does not include the . 22 Rim Fire Magnum or . 22 WRF / . 22 Remington Special ) are constructed with a " heel " ( stem ) on the rear of the bullet which is inserted into case and the case mouth is then crimped around that stem , leaving the majority of the bullet bearing surface exposed and making the diameter of the case and the bullet the same . Although it is possible to handload . 22 rimfire cartridges , the task is far more time - consuming than with regular centerfire cartridges and provides little benefit for the amount of work involved . This is further complicated by the cartridge ' s use of heeled bullets : attempting to extract the original bullet may render it unusable , and attempting to load another bullet may require the use of additional tools to create the needed heel . Reloading a used cartridge is virtually impossible , as the primer is built into the rim of the cartridge itself . Note that the . 22 WMR case diameter is larger than the bullet . This construction method has an inherent weakness in that it provides only minimal protection for the cartridge from exposure to moisture or other elements that adversely affect ammunition reliability . One may take one of these cartridges , hold the case with the fingers of one hand and the bullet between the fingers of the other hand and actually turn ( twist ) the bullet without turning the case ( a little resistance may be encountered at first ) . This means that the seal between the bullet and case is minimal . Overall reliability of today ' s rimfire ammunition is extremely high , but is still considerably lower than centerfire ammunition . Cartridge length . The . 22 LR uses a straight walled case . Depending upon the type and the feed mechanism employed , a firearm which is chambered for . 22 LR may also be able to safely chamber and fire the following shorter rimfire cartridges : . 22 Long Rifle may also be used in firearms chambered for the obsolete . 22 Extra Long . Usage . Today , rimfire rounds are mainly used for hunting small pests , for sports shooting , for plinking , and for inexpensive training . The . 22 LR is the choice for several shooting events : Bullseye , plus divisions of metallic silhouette and pin shooting , most high school , collegiate , Boy Scouts of America , Appleseed Project , 4H shooting events , and many others . Good quality rimfire ammunition can be quite accurate . The main advantages are low cost , low recoil , low noise and high accuracy - to - cost ratio . The main disadvantage is its low power ; it is better suited for use on small game and other small animals ; as a defensive cartridge , it is considered inadequate , though the small size allows very lightweight , easily concealable handguns which can be carried in circumstances where anything larger would be impractical . Despite their limitations , . 22 LR pistols and rifles can kill someone and are often used for self - defense and crime simply because they are prevalent , inexpensive , and widely available to civilians . Most semi - automatic rifles firing . 22 LR cartridges will often only work properly when firing standard or high velocity rimfire ammunition ; subsonic rounds will often not cycle their actions properly . Bolt - action or lever - action rifles , however , can use any of the variants ( high velocity to subsonic ) . Due to the low bolt thrust of the . 22 LR cartridge , most self - loading firearms chambered for the cartridge use the direct blowback operation system . The tiny case of the . 22 LR and the subsonic velocities ( when using subsonic ammunition ) make it well suited for use with a firearm suppressor ( also known as silencers or sound moderators ) . The low volume of powder gases means that . 22 LR suppressors are often no larger than a bull barrel ; the Ruger 10 / 22 and Ruger MK II are common choices , because of their reliability and low cost , and the resulting product is often nearly indistinguishable from a bull barrel model ( although weighing far less ) . Where firearm suppressors are only minimally restricted , a . 22 LR firearm with a suppressor is often favored for plinking , as it does not require hearing protection or disturb the neighbors . Local government agencies sometimes use suppressed rimfire weapons for animal control , since dangerous animals or pests can be dispatched in populated areas without causing undue alarm . The . 22 LR has also seen limited usage by police and military snipers . Its main advantage in this role is its low noise , but it is usually limited to urban operations because of its short range . < ref name = " Ruger 10 / 22 Suppressed Sniper Rifle " > Ruger 10 / 22 Suppressed Sniper Rifle < / ref > The Israeli military used a suppressed . 22 LR rifle in the 1990s for riot control and to " eliminate disturbing dogs prior to operations " , though it is now used less often as it has been shown to be more lethal than previously suspected . Some other examples include the use of suppressed High Standard HDM pistols by the American OSS , which was the predecessor organization of the CIA . Francis Gary Powers was issued a suppressed High Standard for the flight in which he was shot down . Suppressed Ruger MK II pistols were used by the US Navy SEALs in the 1990s . Cartridge dimensions . . 22 Long rifle maximum C . I . P . cartridge dimensions . All sizes in millimetres ( mm ) . The common rifling twist rate for this cartridge is 406 mm ( 1 : 16 in ) , 6 grooves , land width = 2 . 16 mm , Ø lands = 5 . 38 mm , Ø grooves = 5 . 58 mm . According to the official C . I . P . ( Commission Internationale Permanente pour l ' Epreuve des Armes à Feu Portatives ) rulings the . 22 Long Rifle can handle up to P piezo pressure . In C . I . P . regulated countries every rifle cartridge combo has to be proofed at 125 % of this maximum C . I . P . pressure to certify for sale to consumers . Muzzle velocity ( nominal ) . Note : actual velocities are dependent on many factors , such as barrel length of a given firearm and manufacturer of a given batch of ammunition , and will vary widely in practice . The above velocities are typical .