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Air rifle and Air pistol redirect here.

For BB gun (an air gun designed to fire spherical projectiles), see BB gun.

For the Olympic shooting events, see 10 m Air Rifle and 10 m Air Pistol.

For the energy source used in reflection seismology, see Air gun (seismic).

Image:Webley Xocet.jpg

An air gun is a pneumatic gun which fires projectiles using compressed air or other high pressure gas as a propellant.

Contents 1 History 2 Legal issues 3 Air gun power sources 3.1 Spring-piston 3.2 Gas-ram 3.3 Pneumatic 3.3.1 Multi-stroke 3.3.2 Single-stroke 3.3.3 Precharged Pneumatic 3.3.4 CO2 3.4 Safety 3.5 Operating considerations 4 Calibers 5 Ammunition 5.1 Pellet 5.2 BB 6 Choosing an airgun 7 See also 8 References 9 External links

[edit] History

Air guns represent the oldest pneumatic technology having existed since the 15th century. At that time, they presented compelling advantages over the more primitive firearms of the day. For example, air guns could be fired in wet weather (unlike flintlocks) and with greater rapidity than the muzzle-loading guns of the period. Moreover, they were quieter, had no muzzle flash and did not produce telltale clouds of smoke.

Contrary to popular myth, historical military air guns were not silent, though they were much quieter than a firearm of similar caliber. One might safely assume that the sound of an air gun would have been inaudible against the noise of a pitched battle.

For general usage air guns were not a real challenge to the dominant position of powder weapons. They were expensive, delicate, air reservoirs could burst explosively and the valves were not well sealed and slowly leaked pressure. Historical accounts mention common soldiers were often unable to handle the complex guns ^{[citation needed]}, this seems logical in an age where the average peasant recruit had never encountered a machine more complex than a horse-drawn cart. People who had any experience with mechanical devices (millers or clockmakers) were few and far between. The guns of the period were crude and required little skill by the infantryman.

During this period, France, Austria and other nations had special sniper detachments using air rifles. The Austrian 1780 model was named "Windbüchse" (literally "wind rifle") in German. The guns were developed by the gunsmith Bartholomäus Girandoni (1744-1799) and are occasionally referred to as "Girandoni air guns" in literature (the name is occasionally spelled "Girandony"). The Windbüchse (or the Girandoni Air Rifle) was about 4 ft (1.2 m) long and weighed 10 pounds (4.5 kg), which was about the same size and mass as a conventional musket of the time. The air reservoir was a removable, club-shaped butt. The Windbüchse carried twenty .51" (13mm) lead balls in a tubular magazine. A skilled shooter could unload one magazine in about thirty seconds, which was a fearsome rate of fire compared to the slower muzzle loaders of the period. A shot from this air gun could penetrate a one-inch wooden board at a hundred paces, an effect roughly equal to that of a modern 9mm or .45" caliber pistol.

Air guns appear throughout other periods of history. The celebrated expedition headed by Lewis and Clark (1804) reportedly carried a .42" (10mm) reservoir air gun, believed to be produced by Girandoni. It held 22 round balls in a tubular magazine mounted on the side of the barrel. The butt stock served as the air reservoir and had a working pressure of 800 PSI. The rifle was said to be capable of 22 aimed shots in one minute.

During the 1890s, air rifles were used in Birmingham, England for competitive target shooting. Competitions were held in, and between, public houses. Prizes, such as a leg of mutton for the winning team, were paid for by the losing team. The sport became so popular that just after the turn of the 19th century, a National Air Rifle Association was created. During this time over 4000 air rifle clubs and associations existed across Britain, many of them in Birmingham.

Today's modern air guns are typically low-powered due to safety concerns and legal restrictions; however, high-powered designs are still used for hunting. These air rifles can propel a pellet beyond 1100 ft/s (330 m/s), approximately the speed of sound and produce a noise similar to a .22 caliber rimfire rifle. Most low-powered airguns can be safely fired in a backyard or garden, and even indoors, with the proper backstop. In some countries, air guns are still classified as firearms, and as such it may be illegal to discharge them in residential areas. Airguns can be highly accurate and are used in target shooting events at the Olympic Games, governed by the International Shooting Sport Federation (ISSF).

[edit] Legal issues

The legal definition of an airgun differs from country to country; in the United Kingdom, for example, air pistols generating more than 6 foot pounds (8.1 J) or air rifles generating more than 12 foot pounds (16.2 J) of energy are considered firearms, as are airguns in Canada with a muzzle velocity of over 500 ft/s (150 m/s). In Japan, any airgun that fires a metallic projectile is restricted as a firearm, so only airsoft type guns are readily available there. Many US cities and states restrict airgun sales and possession, usually independent of the power; these include: New York City, New York, New Jersey, Michigan, Chicago and Morton Grove Illinois, San Francisco California, or Philadelphia Pennsylvania.

Even airguns not considered firearms are subject to regulation in most areas; at the very least they will be considered dangerous or deadly weapons. There are minimum ages for possession, usually less than the age for firearms. Sales of both airguns and ammunition may be restricted as well. Some areas may require permits and background checks similar to those required for firearms possession. In the UK, Brocock Air Cartridge System air guns, which use a precharged, single shot air cartridge (similar in size to a .38 Special cartridge) were banned after a dozen or so pistols recovered by the police, were found to have been converted by criminals making them capable of firing rimfire ammunition or even .38 Special ammunition. [1]

[edit] Air gun power sources

There are different methods of powering an air gun. These methods can be broadly divided into 3 groups - spring-piston, gas ram and pneumatic.

[edit] Spring-piston

Spring-piston air guns are able to achieve muzzle velocities near the speed of sound from a single stroke of a cocking lever or the barrel itself. The difficulty of the cocking stroke is usually related to the power of the gun, with higher muzzle velocities requiring greater cocking effort.

Spring-piston guns operate by means of a spring-loaded piston in a chamber separate from the barrel. Cocking the gun compresses the spring; pulling the trigger releases it and causes the piston to compress air in the chamber directly behind the pellet. The spring is usually made in the form of a steel coil.

Modern air gun lubricants (such as molybdenum disulfide) are generally designed so that they do not combust at the airgun's operating temperature. Before the availability of synthetic lubricants, when petroleum based products were used, upwards of 30% of the energy of the shot may have come from the burning or "dieseling" of some of the lubricant, according to some writers^{[citation needed]}. The use of such combustible lubricants in modern guns, which are much more highly stressed, can severely damage the spring and piston seals.

Spring-piston guns seem to have a practical upper limit of 1200 ft/s (370 m/s) for .177 cal (4.5 mm) pellets. Higher velocities cause unstable pellet flight and loss of accuracy. Drag increases rapidly as pellets are pushed past the speed of sound, so it is generally better to increase pellet weight to keep velocities subsonic in high-powered guns.

Most spring piston guns are single-shot breach-loaders by nature (somewhat like an old shotgun) but multiple-shot guns have been increasingly common in recent years. Spring guns are typically cocked by a mechanism requiring the gun to be hinged at the mid-point (called a break barrel), with the barrel serving as a cocking lever. Other systems that are used include side levers, under-barrel levers, and motorized cocking, powered by a rechargeable battery.

Spring guns, especially high-powered ones, have a significant recoil resulting from the forward motion of the piston. Although this recoil is less than that of a cartridge firearm, it can make the gun difficult to shoot accurately as the recoil forces are well under way while the pellet is still traveling down the barrel. Most guns seem to respond well to a light, repeatable grip that allows the gun to vibrate the same way from shot to shot. Spring gun recoil also has a sharp forward component, caused by the piston as it hits the forward end of the chamber when the spring behind it reaches full expansion. This sudden forward acceleration helps to counteract the backward recoil, since the backward and forward recoil forces happen within milliseconds of each other, but it is infamous for knocking around and loosening the lenses and reticles found in telescopic sights, even those which are designed to withstand the (backward-only) recoil from high-powered firearms. On any but the lowest power spring guns, any mounted telescope should be airgun-rated.

Spring guns can also suffer from spring vibrations that upset accuracy. These vibrations can be controlled by adding features designed into the gun, like close-fitting spring guides, or by aftermarket tuning done by airgunsmiths who specialize in airgun modifications. A common modification is the addition of viscous silicone grease to the spring, which both lubricates it and damps out vibration.

The better quality spring air guns can have long service lives, often exceeding thirty years. Because they deliver the same energy on each shot, the trajectory is extremely repeatable. This repeatability resulted in most Olympic air gun matches through the 1970s and into the 1980s being shot with spring-piston guns. Beginning in the 1980s, guns powered by compressed, liquefied carbon dioxide began to dominate competition. Today, the guns used at the highest levels of competition are powered by compressed air stored at very high pressures of 2000 to 3000 lbf/in² (14 to 21 MPa).

The Chinese army uses spring-piston small arms to train more economically. These military-issue Chinese spring-piston air-guns are often available by mail-order, but the buyer should note that quality control on these guns tends to be somewhat variable.

[edit] Gas-ram

Some more expensive makes of air rifle (e.g. Weihrauch) incorporate; part supplied by Theoben). Pressurized air or nitrogen is held in a special chamber built into the piston, and this air is further pressurized when the gun is cocked. It is, in effect, a gas spring more commonly reeferred to as a "gas-ram" or "gas strut". Gas-ram rifles require higher precision to build, since they require a low friction sliding seal that can withstand the high pressures when cocked. The advantages of the gas-ram include the facility to keep the rifle cocked and ready to fire for long periods of time without harming the mechanism. Also, due to the absence of a spring (and therefore a reduction in moving mass during firing) there is less (although some say slightly sharper), recoil. There is also an elimination of the associated problems of long-term spring fatigue and a faster "lock time" (the time between pulling the trigger and the pellet being discharged). The improvement in lock time makes for better accuracy due to there being less time for the gun to move or wobble off target.

[edit] Pneumatic

Pneumatic-type airguns require the pre-compression of air in a chamber prior to the gun being used. Similar to the spring type, they are cocked or charged using a lever. When fired, the compressed air in the chamber is used to force the projectile out. Due to this design, the amount of recoil is almost zero as there is no significant movement of mechanical parts during the firing cycle. These air guns may also be powered by CO₂ stored in capsules or cylinders, and filled via a hand pump or dive tank.

[edit] Multi-stroke

Multi-Stroke pneumatic airguns require 2-10 pumps of an on-board lever to store compressed air within the airgun. Variable power can be achieved through this process, as the user can adapt the power level for long, or short-range shooting. The design of higher quality and match-grade multi-stroke air rifles can propel a pellet to speeds in excess of 700-800 feet per second.

For beginners and intermediates, multi-stroke air rifles have been a cost-effective choice as they are generally the cheapest form of airgun available. Several manufacturers make multi-stroke airguns including, to name a few, Benjamin, Daisy, and Crosman.

[edit] Single-stroke

As the name implies, one motion of the cocking lever is all that is needed to compress the air for propulsion. At first glance, this design would seem to offer lower power than multi-stroke airguns, though this is not the case. This method of compressing air is found on cheaper target-shooting rifles as it is less strenuous than a multi-stroke, aiding accuracy.

[edit] Precharged Pneumatic

Pre-charged pneumatic (PCP) airguns can be used for hunting and competition. These are usually filled by decanting from an air reservoir, such as a diving cylinder or by charging directly with a hand pump. Because of the need for cylinders or charging systems, PCP guns have higher initial costs but very low operating costs compared to CO₂ guns. These guns are often used for hunting purposes in countries other than the U.S. because of restrictive firearm laws.

PCP guns have very low recoil and can fire many shots (from fewer than 30, to as many as 500 [2]) from one filling, and because of the ready supply of gas are ideal for repeating mechanisms. Several manufacturers produce repeating PCP guns, usually with rotary magazines of 8 - 16 shot capacity. PCP guns are very popular in the UK and Europe due to their accuracy and ease of shooting. They are widely utilised in the sport of Field Target shooting, [3] fitted with high magnification optical scopes for accurate rangefinding. [4] There is currently a craze in the U.S. for big-bore pre-charged pneumatic air rifles. Many of these, such as the .45,.50 and .68 calibre paintballs are expensive, but are among the most powerful air guns manufactured. See also Airsoft.

Many PCP guns have been used for hunting. In some countries the use of a sound moderator or silencer makes these rifles particularly quiet, an advantage for hunters. One of the traditional rifles for hunting wolves in Russia was said to be a large-calibre reservoir air-rifle.^{[citation needed]} It is said to have shot silently to avoid warning the pack, though such guns are actually surprisingly loud. Modern reservoir guns in larger calibers (6 to 9 mm) are often used for hunting small game in the U.S.

Earlier hand pumps for charging carried with them problems of fatigue (both human and mechanical), temperature warping, and condensation. None of those is beneficial to good shooting or the longevity of the rifle. More modern design hand pumps with built-in air filtration and drying overcome many of these problems. Using scuba-quality air decanted from a scuba cylinder provides a clean, dry, high-pressure air supply that is consistent and available at low cost.

During the discharge cycle, the hammer of the rifle is released by the sear to strike the valve. This usually involves the hammer moving toward the rear of the rifle, unlike firearms where the hammer normally moves forward. Prior to being struck by the hammer, the valve is held closed by a spring and the pressure of the air in the gun’s tank. The pressure of the spring is constant and the pressure of the air changes with each successive shot. As a result, when the tank pressure is at its peak, the valve permits passage of less total volume of air than when the tank pressure has been reduced by a series of shots. This results in a somewhat greater consistency of velocity from shot to shot than would otherwise be expected, and accuracy with a rifle is usually dependent on consistency.

Most of the currently available PCP rifles are of very good to superlative quality^{[citation needed]}. Their forte is accuracy, not raw power. This makes them popular with the competent, disciplined shooter. Harnessing this accuracy is benefited by the use of a quality telescopic sight.

The PCP is valuable to the small game hunter, pest controller, dedicated target shooter, marksmanship instructor and any other who requires precision, over the higher power of a firearm. However, they can also be powerful. Denis Quackenbush, an American gunsmith, produces a 500 foot pound .457 caliber air rifle that is used for hunting deer-sized game. The spectrum of available choices in this field is such that most shooters can find a preference in style. There are also very high-quality target pistols available in PCP.

[edit] CO₂

Most CO₂ guns use a disposable cylinder, a powerlet, that is purchased prefilled with 12 grams of liquefied carbon dioxide, although some, usually more expensive models, use larger refillable CO₂ reservoirs like those typically used with paintball markers.

Carbon dioxide-powered guns have two significant advantages over precharged pneumatic air guns: (1.) A simpler system for compact storage of energy - a small volume of liquid converts to a large volume of pressurized gas. (2.) No pressure regulator. Within a temperature range tolerable to humans there is little need to regulate the inherently suitable pressure for low-to-moderate-power air guns. The vapor pressure is dependent only on temperature, not tank size, as long as some liquid CO₂ remains in the reservoir.

These two advantages allow CO₂ guns to be constructed more simply than guns using a pressurized air reservoir. Some CO₂-powered guns have detachable or fixed reservoirs that are loaded with pressurized gas from a larger cylinder. Most CO₂ powered guns use the standard 12 gram Powerlet disposable cylinder invented by Crosman. Recently Crosman has introduced a new 88 gram disposable AirSource cylinder that is used in some of their guns; it has yet to receive wide use by other manufacturers.

CO₂ guns, like compressed air guns, offer power for repeated shots in a compact package without the need for complex cocking or filling mechanisms. The ability to store power for repeated shots also means that repeating arms are possible. There are many replica revolvers and semiautomatic pistols on the market that use CO₂ power. These guns are popular for training, as the guns and ammunition are inexpensive, safe to use, and no specialized facilities are needed for safety. In addition, they can be purchased and owned in areas where firearms possession is either strictly controlled or banned outright.

Most CO₂ powered guns are relatively inexpensive, although there are still a few precision target guns on the market that use CO₂.

The CO₂ system has been used in experimental non-lethal law enforcement weapons, where high power delivery systems launch rubber batons or bean bags out of a gas-powered launcher, much like a non-lethal shotgun system (but at lower velocities, thus being safer).

[edit] Safety

For safety, CO₂ containers should be kept at temperatures below 120 degrees F; at temperatures above this level, the pressure begins to increase very rapidly, and can cause the container to fail. CO₂ containers with diameters at or above two inches (50 mm) have a pressure release "rupture" mechanism to release the contents over a certain pressure level and avoid explosion due to high temperature. These disks are generally calibrated to a minimum pressure corresponding to the 120 degree F level at 100% of the rated CO₂ capacity. Elevated temperatures, even those below the critical temperature, can cause increased leaking through seals.

[edit] Operating considerations

• Refilling Forcing more carbon dioxide gas into a reservoir of liquid and gas CO₂ while maintaining a constant temperature would not raise the pressure but merely convert the additional gas into liquid. By chilling the vessel to be filled, the lower vapor pressure will pull CO₂ from the source container. While the pressure in the resevoir is generally dependent only on the temperature, if the bottle is too full, that changes. The expansion of the liquid CO₂ will take up all the space in the bottle, preventing evaporation. At this point, the pressure increase with temperature becomes dangerously high.[5]
• Cooling Each time the gun is fired there is some evaporation of liquid to gas which is an endothermic process in which the pressure drops until enough ambient heat is absorbed to restore the pressure. When shooting at a rate faster than the cylider can absorb heat from the environment to counter the cooling of the evaporating liquid, the pressure will drop, and the velocity is likely to drop as well in a non-regulated gun.

[edit] Calibers

Image:Pellet Sizes.jpg

Airguns are most commonly found in the following calibers:

• .177" (4.5mm) - the most common caliber, also used in ISSF shooting events at the Olympic Games.
• .20" (5mm) - found in some European airguns and those manufactured by US airgun manufacturer, Sheridan.
• .22" (5.5mm) - the most common caliber for hunting small game.
• .25" (6.35mm) - the largest commonly available caliber.

Ballistic modelling software is able to illustrate the benefits and disadvantages of each calibre at various power levels.

Larger calibers do exist, for example a Korean manufacturer sells air rifles in .36" (9mm) and larger ^{[citation needed]}. Custom airgun manufacturers regularly produce air rifles in common muzzleloading rifle calibers too, such as .45" (11.25 mm), .50" (12.5 mm), .58" (14.5 mm) and larger. These large bore airguns, are made by US airgun manufacturer Dennis Quackenbush. Quackenbush rifles have been used to take almost every type of large game including Elk, and many African species up to Kudu.

Gary Barnes is another large bore airgun manufacturer, whose handmade airguns are suitable for for hunting medium sized game.

[edit] Ammunition

[edit] Pellet

The typical projectile used in rifled airguns is the lead diabolo pellet. This is a waisted projectile hollowed at the base and available in a variety of head styles. The diabolo pellet is designed to be drag stabilized, though is not as stable as some other shapes in the transonic region.

While some high-power Spring-piston air rifles can propel light pellets at, or beyond, the speed of sound, this results in decreased accuracy and often decreased life of the rifle's spring and seals. This is due to a lighter pellets tendency to move along a barrel before maximum pressure is reached, resulting in loss of the 'air cushion' and subsequent collision of the piston and/or seal into the end of the air chamber at high velocity.

Most air guns have a caliber of .177 (4.5 mm) or .22 (5.6 mm), and are designed for target practice, small game hunting and field target shooting. Cost per round is less than $0.02 (US) for Olympic-quality ammunition, and far less for cheaper grades. Though less common, .20 and .25 caliber (5.0mm and 6.4mm) guns also exist and are used predominantly for hunting.

[edit] BB

Image:Daisy Model 499.jpg The BB was once the most common air gun ammuition in the USA. A BB is a small ball usually made of steel with a copper or zinc coating. BBs can be very accurate at short distances when fired from properly designed BB guns. The Daisy Model 499 was specifically designed for target competition at 15' using precision-ground BBs. However, because BBs are not fired from rifled barrels, as are pellets, they lack the spin stabilisation that gives pellets long-range accuracy. Typically BBs are used for indoor practice, casual outdoor plinking, training children or for airgun enthusiasts who like to practice but cannot afford pellet utilising, high-power airgun systems.

Some shotgunners use sightless BB rifles to train in instinctive shooting. Similar guns were also used briefly by the United States Army in the 1960s as part of an instinctive shooting program termed "Quick Kill".^{[citation needed]}

[edit] Choosing an airgun

• Self-contained: spring-piston, multi-stroke pneumatic, single-stroke pneumatic. These guns require no additional CO₂ cylinders or external pumps, and are thus cheaper to operate.
• Noise Level: spring-piston. Absence of loud gas discharges makes these guns quieter to operate. Consider when practicing in cramped urban areas. Where legal, a good quality suppressor (commonly referred to as a silencer or moderator) can make other types as quiet as a piston rifle.
• Accuracy: pre-charged, single-stroke pneumatic, recoilless piston. Without the variable factor introduced by CO₂ vapor pressure or the recoil introduced by the spring, the mechanisms in these guns have more repeatable shots.
• Convenience: pre-charged or CO₂ powered. These guns don't require constant cocking, and are hence more popular with recreational shooters.

The above points are generalizations. The overall performance of your airgun will depend on its quality. For instance, a match-grade CO₂ rifle will have better accuracy than a cheaper spring-piston gun. The extra cost translates into higher quality, better accuracy, tighter tolerances and so forth.

When choosing an air rifle or an air pistol consider where (club range, backyard, condo, farm) and how (competition, target practice, plinking, pest-control) you plan to use it.

[edit] See also

• Marksmanship
• Airsoft
• BB gun
• Gun Quarter
• Girandoni Air Rifle

[edit] References

• History of Air guns
• Introduction to Modern Air Gun Technology

[edit] External links

Safety

• Air gun safety

Animations / Demonstrations

• Animations, demonstrations, schematics and the setting up of Air rifles and their optics

Ballistic Modelling software

• Chairgun

History

• The history and origins of the air rifle
• Girandoni style air rifles and pistols and preliminary research presentation
• Lewis and Clark's air rifle

Manufacturers

• AirForce
• Anschütz
• Air Arms
• Brocock
• BSA
• Crosman (also Benjamin Sheridan)
• Daystate
• Dynamit Nobel RWS
• Diana
• Falcon (owned by Air Arms)
• Feinwerkbau
• FX Airguns
• Gamo
• Gunpower
• Logun
• Ripley
• Roehm
• Shanghai
• Steyr
• Theoben
• Walther
• Webley & Scott
• Weihrauch

Custom Manufacturers

• Barnes Pneumatic
• Crooked Barn
• Theo Hegmans
• ISP
• Skanar
• Quackenbush
• Whiscombe

Hand Pumps and Compressors

• Hill Pumps
• Distributor of Alkin Compressors

Reviews

• Straight Shooters
• American Airgun Hunter
• Pyramid Air

Books

• Big Spring Guns

Clubs and Special Interest Groups

• American Airgun Field Target Association
• British Field Target Association
• United Kingdom Association for Hunter Field Target
• National Small Bore Rifle Association (United Kingdom)
• International Shooting Sport Federationda:Luftriffel

de:Luftgewehr ko:공기소총 id:Senapan angin he:רובה אוויר nl:Luchtgeweer ja:空気銃 no:Luftgevær pl:Wiatrówka simple:Air gun sl:Zračna puška fi:Ilmakivääri