Air Rifle

Air guns or rifles have come a long way since their first incarnation in the 1500's. These days the two most common types are Springer (spring piston) rifles or PCP rifles(pre charged pneumatic).

Spring-piston

Spring-piston rifles 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.
Most spring piston guns are single-shot breech-loaders by nature, but multiple-shot guns have become more 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 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 travelling 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 recoil, since the recoil and "forward recoil" forces happen within milliseconds of each other, but it is infamous for the loosening or breaking of lenses and reticles found in low- and medium-priced telescopic sights. All mounted telescopic sights for air guns should be rated as such.
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, their trajectory is consistent. Most Olympic air gun matches through the 1970s and into the 1980s were shot with spring-piston guns, often of the opposing-piston recoil-eliminating type.

Pre-charged pneumatic (PCP)

Pre-charged pneumatic (PCP) air rifles 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 rifles have higher initial costs but very low operating costs. These rifles are often used for hunting purposes in countries with restrictive firearms laws.
PCP rifles have very low recoil and can fire as many as 500 shots per charge. The ready supply of air has allowed the development of semi-automatic PCP air rifles. PCP rifles are very popular in the UK and Europe because of their accuracy and ease of shooting. They are widely utilized in ISSF 10 metre air pistol and rifle shooting events and the sport of Field Target shooting, and fitted with telescopic sights.
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. Modern hand pumps have built-in air filtration systems and have overcome many of these problems. Using scuba-quality air decanted from a scuba cylinder also provides a clean, dry, high-pressure air supply that is consistent and available at low cost.
During the typical PCP's 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 reservoir. The pressure of the spring is constant, and the pressure of the air decreases with each successive shot. As a result, when the reservoir pressure is at its peak, the valve opens less fully and closes faster than when the reservoir pressure is lower, resulting in a similar total volume of air flowing past the valve with each shot. This results in a degree of self-regulation that gives a greater consistency of velocity from shot to shot than would otherwise be expected. A well-designed PCP will display good self-regulation properties, meaning good shot to shot consistency over a range of pressures as the air reservoir is diminished.
More expensive PCP rifles and pistols are often pressure regulated, i.e. the firing valve operates within a secondary chamber separated from the main air reservoir by the regulator body. The regulator maintains pressure within this secondary chamber at a set pressure lower than the main reservoir's. This occurs until the main reservoir's pressure is diminished to the set pressure, after which the PCP behaves in an unregulated manner. Thus shot to shot consistency is maintained for longer than in an unregulated rifle, at the expense of efficiency, shots per fill and often at a lower velocity.
At M.T.S.C the majority of air rifle owners use P.C.P. rifles. Popular and reliable makes include Air Arms, Weihrauch and Daystate. We would ALWAYS advise you come down and have a chat before you purchase a rifle so we can offer sound advice and let you know the pitfalls of purchasing the wrong rifle before you make any hasty decisions. The same goes for purchasing telescopic sights and other equipment. We also work closely with local firearms suppliers who should be able to offer you a good deal when you first enter the world of shooting.
Air rifle or pistol shooting at M.T.S.C. is proving an ever more popular sport and has a great social aspect to it. You are welcome to visit us (free of charge) to get an idea as to what's involved, how much it will cost and to see what discipline takes your fancy at any time we are open. Feel free to browse the rest of our site and we look forward to meeting you some time soon.