Tuesday, July 22, 2008

How to Use an Air Rifle in Sports Shooting

Teach kids sports shooting safety with an air rifle! An air rifle is a great tool when kids are learning the basics of sports shooting. Air rifles don't kick like a high powered rifle, so kids can handle an air rifle easier. High school 4-H Clubs have air rifle teams. So do the Olympics. Follow these basic steps for kids and adults alike to have a blast with air shooting!

Step1
Purchase a spring discharge or compressed air discharge gun. Any local sporting goods store that carries guns can help you choose.

Step2
Buy a supply of paper targets. They can be found in most sporting goods stores and many discount stores. Steel targets are also used in many competitions. You'd be surprised at how forcefully a compressed air discharge gun can knock down a steel man!

Step3
Mount the air rifle just as you would any rifle, with your head down and face against the stock. Air rifles are a great tool for working with eye-to-hand coordination.

Step4
Relax and keep your eye on the center of your target. A firm squeeze of the trigger and concentration will bring success.

Tips & Warnings
  • Whether you practice in your own backyard or go to your local shooting range, you can build your skills. Do it just for fun, or get ready to compete. With an air rifle, the sky's the limit.
  • Keep your paper targets to look back on over time. They can help you see and track your progress. You can even frame the best ones!

By, eHow

How to Buy an Air Rifle

Whether you're buying your son or daughter his or her first Daisy BB gun or buying yourself an expensive air rifle for NRA competition, choosing the right air rifle is important. Getting the right air rifle depends greatly on the purpose for your gun. There are many applications for air rifle use. Getting the right rifle for the right task is your first step.


Step1
Determine what you will be doing with the air rifle. Is it for indoor air rifle competition? Is it for outdoor competition? Will you be using the air rifle for varmint hunting? Will it be used for small pest control? Is it merely for plinking cans in the back yard? These are all things which must be considered before investing too much money into an air rifle.

Step2
Research the different brands of air rifles. There are quite a few brands out there, such as: Crosman, Daisy, Airforce, Beeman, Benjamin & Sheridan, Winchester and Tech Force. Each type of rifle is best suited for a particular application. Remember, when talking about air rifles, these actually have rifling in the barrel; which makes them a rifle and not an air gun. A BB gun is an example of an air gun since it has a smoothbore barrel. Keep that in mind if you truly want a .22 caliber quality air rifle and not just a pellet gun.

Step3
Go to a local retailer, or buy your air rifle online. Make sure that you get the correct ammo for your rifle. Each type of ammunition has a specific function. There are four basic types of ammo for air rifles: wadcutter, for paper target competition; pointed, for field use and better penetration; hollow point for silhouette competition; and round nose, used when knock-down power is important.

Tips & Warnings
  • ALWAYS keep the gun pointed in a safe direction.
  • ALWAYS keep your finger off the trigger until ready to shoot.
  • ALWAYS keep the gun unloaded until ready to use.
  • Air rifles are NOT TOYS! The same care and precautions used with firearms should also be used with any air rifle or air gun.

By, eHow

Thursday, July 10, 2008

CO2

Most CO2 guns use a disposable cylinder, a powerlet, that is purchased pre-filled 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 pre-charged 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, the same company introduced a new 88 gram disposable AirSource cylinder that is used in some of their guns.

On the other hand, liquefied CO2 must be purchased, which introduces an element of cost that does not factor with a PCP gun/hand pump combination using "free" air, or is at least considerably lower when refilling from a diver's tank.

Furthermore, the pressure of gaseous CO2 at ordinary ambient temperatures is only around 850–1000 psi (6 to 7 MPa), which is only a third of the safe working pressure of a typical full PCP reservoir (20 MPa or 2900 psi or more). The effect of this is that generally speaking CO2 guns are lower powered and less efficient than PCP guns, which is why CO2 guns are usually pistols or semi-target type rifles, with few guns (none of commercial note) reaching even the 12 ft (3.7 m)·lbf (16.2 joules) licence-free energy limit for air rifles imposed in the UK.

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 semi-automatic 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).

Article source From Wikipedia, the free encyclopedia

Pneumatic

Pneumatic airguns utilize pre-compressed air as the source of energy to propel the projectile. Single-stroke and multi-stroke guns utilize an on board pump to pressurize the air in their reservoir, Pre-charged Pneumatic guns' reservoirs are filled using either a high-pressure hand pump (often capable of attaining pressures of 30 MPa) or by decanting the necessary volume/pressure of air from a diving cylinder. Because of this design, having no significant movement of heavy mechanical parts during the firing cycle, the recoil produced is only the "true" recoil, equivalent to the equal and opposite reaction to the pellet and air volume's acceleration up the bore.

Multi-stroke

Multi-Stroke pneumatic air guns require 2-10 pumps of an on-board lever to store compressed air within the air gun. 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 1,000 feet per second (300 m/s).
For beginners and intermediates, multi-stroke air rifles have been a cost-effective choice as they are generally the cheapest form of air gun available. Several manufacturers make multi-stroke air guns including, to name a few, Sheridan, Benjamin, Daisy, and Crosman. Modified multi-pump guns, with stronger pump linkages and improved valves, can produce muzzle energies in excess of 30 foot-pounds force (41 J) (from inexpensive guns. Modification kits for Sheridan and Benjamin rifles are available from commercial suppliers.

Single-stroke

As the name implies, one motion of the cocking lever is all that is needed to compress the air for propulsion. The single-pump system is usually found in target rifles and pistols, where the higher muzzle energy of a multi-stroke pumping system is not required.

Pre-charged 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 were the very first air guns; an experimental gun was made for King Henry IV of France in 1600. The Austrian military issued air rifles designed by Girandoni to special troops in the late 18th and early 19th century.
PCP guns have very low recoil and can fire from fewer than 30, to as many as 500 shots per charge. The ready supply of gas, has allowed the development of semi-automatic PCP air guns. Though technology allows this design, these types of PCP airgun are not permitted in certain countries, e.g. the United Kingdom. PCP guns are very popular in the UK and Europe because of their accuracy and ease of shooting. They are widely utilized in the sport of Field Target shooting, [14] and fitted with telescopic sights.
PCP guns are frequently used for hunting. In some countries, the use of a sound moderator or silencer makes these rifles particularly quiet, an advantage for hunters. Modern reservoir guns in larger calibers (6 mm 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 systems 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. The hammer may move rearwards or forwards, unlike firearms where the hammer almost always 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 air 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 mainly dependent on consistency.
The better PCP rifles and pistols are often regulated, i.e. the valve operates within a secondary chamber within which the air pressure is kept constant for a set number of shots, rather than directly within the main reservoir. The pressure within this secondary chamber is maintained at a lower pressure than the pressure in the main reservoir by means of a regulator. Thus shot to shot consistency is far greater than in an unregulated rifle, at least as long as the pressure in the main reservoir is higher or equal to the regulated pressure in the secondary chamber. Beyond this point, the rifle or pistol will operate as any unregulated gun, and velocities drop rapidly.
The PCP is valuable to the small game hunter, pest controller, dedicated target shooter, marksmanship instructor and any other who requires precision, rather than the firepower of a firearm.

Article source From Wikipedia, the free encyclopedia

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. For example Gamo's Hunter Extreme at 1,600 ft/s (490 m/s) has a cocking effort of 58 lb (26 kg) while those shooting 1,000 ft/s (300 m/s) or 1,250 ft/s (380 m/s) usually require only 33 lb (15 kg).

Spring-piston guns operate by means of a coiled steel spring-loaded piston contained within a compression chamber, and separate from the barrel. Cocking the gun causes the piston assembly to compress the spring until a small hook on the rear of the piston engages the sear; pulling the trigger releases the sear and allows the spring to decompress, pushing the piston forward, thereby compressing the air in the chamber directly behind the pellet. Once the air pressure has risen enough to overcome any static friction and/or barrel restriction holding the pellet, the pellet moves forward, propelled by an expanding column of air. All this takes place in a fraction of a second, during which the air undergoes adiabatic heating to several hundred degrees during compression, and then cools as the air expands once more.

Modern air gun lubricants are generally a compounded mix of ingredients, such as silicone paste and molybdenum disulfide. These compounds are designed to not burn at the temperatures reached in airgun compression chambers, however it seems that any form of lubricant will burn to some extent at these elevated temperatures. Before the availability of synthetic lubricants, when purely petroleum based products were used, some writers claimed that upwards of 30% of the energy of the shot may have come from the burning of some of the lubricant although this has been debated by others. The Cardews experimented by firing a spring-piston air rifle within a nitrogen-only enclosure, thus eliminating oxygen and preventing any form of combustion. The resultant shots fired displayed very noticeably reduced power when compared to the same setup fired both before and after the experiment outside of the enclosure, i.e. within the Earth's atmosphere. The limited burning of very small quantities of lubricant is not to be confused with "dieseling" which occurs when volatile fractions and vapours of petroleum-based lubricants burn violently, generally the result of excessive lubricant finding its way (or deliberately placed) ahead of the piston. This can and often does severely damage the spring and piston seals, and in extreme cases cause the cylinder to bulge, especially in modern, more highly stressed guns. Dieselling is noticeable also because the gun emits a very loud report, often comparable to that produced by a .22 Short rimfire cartridge, some muzzle flash, and smoke.

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.[citation needed] However, the longer lighter pellets can achieve good accuracy and surprising high speed (the Gamo hunter extreme can reach 1,600 ft/s (490 m/s) with their special pellets). 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. Many shooters have found that velocities in the 800 - 900 ft/s (270 m/s) range offer an ideal balance between power and pellet stability.[citation needed]

Most spring piston guns are single-shot breech-loaders by nature (somewhat like a single or double barreled 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 or breaking the lenses and reticles found in low and medium priced 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 air gun rated.

Spring guns can also suffer from spring vibrations that can 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 air gun modifications. A common modification is the addition of viscous silicone grease to the spring, which both lubricates it and damps out vibration.[citation needed]

The better quality spring air guns can have very long service lives, being simple to maintain and repair. Because they deliver the same energy on each shot, the trajectory is extremely consistent. This resulted in most Olympic air gun matches through the 1970s and into the 1980s being shot with spring-piston guns, albeit often of the opposing-piston recoil-eliminating type. 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 lb/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. Similarly, the Romanian army formerly used spring-piston, single shot, 4.5 mm training rifles to train entry level recruits, prior to switching them to .22 LR training rifles.

Some makes of air rifle (e.g. Weihrauch, Theoben) incorporate a gas spring instead of a mechanical spring. 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 commonly referred to as a "gas ram" or "gas strut". Gas spring 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 spring include the facility to keep the rifle cocked and ready to fire for long periods of time without harming the mechanism. Also, since there is no 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 since there is less time for the gun to move off target.

Air gun power sources

There are different methods of powering an air gun. These methods can be broadly divided into 3 groups - spring-piston, pneumatic, and CO2. These methods are used in air rifles and air pistols.

source From Wikipedia, the free encyclopedia

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 matchlocks) and with greater rapidity than the muzzle-loading guns of the period. Moreover, they were quieter than a firearm of similar caliber, had no muzzle flash and were completely smokeless, not disclosing the shooter's position on firing. Black powder guns of the 18th and 19th century produced huge volumes of dense smoke on firing, giving air rifles an advantage over them. One might also 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. Their expensive, delicate, air reservoirs could burst explosively and the valves were not well sealed and slowly leaked pressure.

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 in 1778 or 1779 by the Tyrolese watchmaker, mechanic and gunsmith Bartholomäus Girandoni (1744-1799) and are occasionally referred to as "Girandoni air guns" in literature (the name is occasionally spelled "Girandony"; "Giradoni" or "Girardoni" . 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" (13 mm) 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 9 mm or .45" caliber pistol

Around 1820, the Japanese inventor Kunitomo Ikkansai developed various manufacturing methods for guns, and also created an air gun based on the study of Western knowledge ("rangaku") acquired from the Dutch in Dejima.

Air guns appear throughout other periods of history. The celebrated expedition headed by Lewis and Clark (1804) reportedly carried a .42" (10 mm) 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.

During this time, the air gun was associated with poaching because it could deliver a shot at a relatively quiet level. A modern reproduction of an air cane copied accurately from one in the Royal Armouries, Leeds, UK by Baker and Currie gives a performance of around 480 feet (150 m) per second (ft/s) for a 51.5 grain (3.33 g) 32 calibre lead ball. The reproduction was charged to 600 pounds per square inch (14 MPa) and the first shot registered only 272 ft/s (83 m/s), indicating this is a realistic maximum pressure given that the release valve failed to open properly against the high pressure of air in the reservoir. The velocities were reasonably constant for the next five shots, after which they progressively diminished by about 20 ft/s (6.1 m/s) per shot, though this figure is not exact. In an experimental simple home-made large calibre air gun with a three metre barrel Middleton obtained a maximum velocity of 599 ft/s (183 m/s) for a 50 calibre 140 grain (9.1 g) lead ball, and 411 ft/s (125 m/s) from a 2 metre barrel with a .527 calibre 220 grain (14.3 g) lead ball, using a pressure of only 100 pounds per square inch pumped with a bicycle pump . Reilly, a London gunmaker specialising in air guns, writing around 1850 states that he was able to produce a pressure of a little under 500 pounds per square inch using the direct stroke pump of the time. He does not give muzzle velocities. Wesley (op.cit., pp. 35-6) shot an antique air cane bullet of 3/4 inch diameter into the cast iron fireplace of his workroom, and demolished the fireplace, stripped the wallpaper off the walls, and blew all his oils and chemicals off the mantleshelf.

Today's modern air guns are typically low-powered because of 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. Using lead pellets, many current spring powered .177 pellet guns can break the sound barrier, and one, the Gamo 1250, can reach 1,600 ft/s (490 m/s) with these new pellets. 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. Air guns can be highly accurate and are used in target shooting events at the Olympic Games, governed by the International Shooting Sport Federation (ISSF).