An air gun
pellet is, for the most part, a non-spherical projectile designed to be fired from an
air gunAn air gun is a rifle, pistol, or shotgun which fires projectiles by means of compressed air or other gas, in contrast to a firearm which burns a propellant. Most air guns use metallic projectiles as ammunition...
. But this is not always the case.
Pellets differ from
bulletA bullet is a projectile propelled by a firearm, sling, or air gun. A bullet does not contain explosives, but damages the intended target by its impact or penetration...
s used in
firearmA firearm is a device which projects either single or multiple projectiles at high velocity through a controlled explosion. The firing is achieved by the gases produced through rapid, confined burning of a propellant. This process of rapid burning is technically known as deflagration...
s because of the
pressurePressure is the force per unit area applied in a direction perpendicular to the surface of an object. Gauge pressure is the pressure relative to the local atmospheric or ambient pressure.- Definition :...
s encountered; firearms operate at pressures of thousands of
atmospheresAtmospheric pressure is defined as the force per unit area exerted against a surface by the weight of air above that surface at any given point in the Earth's atmosphere. In most circumstances atmospheric pressure is closely approximated by the hydrostatic pressure caused by the weight of air above...
, while airguns operate at pressures as low as 50 atmospheres. Firearms have sufficient pressure to force a slightly over-sized bullet to fit the bore in order to form a tight seal, while airguns generally use a slightly undersized projectile that is designed to obdurate upon shooting so as to seal the bore, and engage the
riflingRifling is the helix-shaped pattern in the barrel of a gun or firearm, which imparts a spin to a projectile around its long axis. This spin serves to gyroscopically stabilize the projectile, improving its aerodynamic stability and accuracy....
.
An air gun
pellet is, for the most part, a non-spherical projectile designed to be fired from an
air gunAn air gun is a rifle, pistol, or shotgun which fires projectiles by means of compressed air or other gas, in contrast to a firearm which burns a propellant. Most air guns use metallic projectiles as ammunition...
. But this is not always the case.
Pellets differ from
bulletA bullet is a projectile propelled by a firearm, sling, or air gun. A bullet does not contain explosives, but damages the intended target by its impact or penetration...
s used in
firearmA firearm is a device which projects either single or multiple projectiles at high velocity through a controlled explosion. The firing is achieved by the gases produced through rapid, confined burning of a propellant. This process of rapid burning is technically known as deflagration...
s because of the
pressurePressure is the force per unit area applied in a direction perpendicular to the surface of an object. Gauge pressure is the pressure relative to the local atmospheric or ambient pressure.- Definition :...
s encountered; firearms operate at pressures of thousands of
atmospheresAtmospheric pressure is defined as the force per unit area exerted against a surface by the weight of air above that surface at any given point in the Earth's atmosphere. In most circumstances atmospheric pressure is closely approximated by the hydrostatic pressure caused by the weight of air above...
, while airguns operate at pressures as low as 50 atmospheres. Firearms have sufficient pressure to force a slightly over-sized bullet to fit the bore in order to form a tight seal, while airguns generally use a slightly undersized projectile that is designed to obdurate upon shooting so as to seal the bore, and engage the
riflingRifling is the helix-shaped pattern in the barrel of a gun or firearm, which imparts a spin to a projectile around its long axis. This spin serves to gyroscopically stabilize the projectile, improving its aerodynamic stability and accuracy....
. Since pellets may be shot through a
smoothboreA smoothbore weapon is one which has a barrel without rifling. Smoothbores range from handheld firearms to powerful tank guns and large artillery mortars.-History of firearms and rifling:...
barrelA gun barrel is the tube, usually metal, through which a controlled explosion or rapid expansion of gases are released in order to propel a projectile out of the end at a high velocity....
, they are often designed to be inherently stable, much like the Foster slugs used in smoothbore shotguns.
The "diabolo," sometimes called
wasp waist pellet is the most common design found today.
The diabolo pellet can have a flat, round, hollow or pointed tip, followed by a taper to a thin
waistThe waist is the part of the abdomen between the rib cage and hips. On proportionate people, the waist is the narrowest part of the torso.Waistline refers to the horizontal line where the waist is narrowest, or to the general appearance of the waist...
. From the waist back, the pellet is hollow, and flares out to full diameter when pressurized by the gun. The head, or solid part in front of the waist, is usually sized to fit the
boreThe term caliber designates the inside diameter of a tube, the diameter of a solid wire or rod, or a measurement of the length of a gun relative to its diameter....
just touching the
riflingRifling is the helix-shaped pattern in the barrel of a gun or firearm, which imparts a spin to a projectile around its long axis. This spin serves to gyroscopically stabilize the projectile, improving its aerodynamic stability and accuracy....
. This keeps the pellet centered in the bore, while keeping the friction as low as possible. The effect of friction is used in order to keep the pellet stationary until the piston has reached the end of its travel, compressing as much as air as is inherently possible. The skirt of the pellet is thin, and made of a malleable material, usually
leadLead is a main-group element with symbol Pb and atomic number 82. Lead is a soft, malleable poor metal, also considered to be one of the heavy metals. Lead has a bluish-white color when freshly cut, but tarnishes to a dull grayish color when exposed to air...
, although non-toxic alternatives are available that use
tinTin is a chemical element with the symbol Sn and atomic number 50. It is a main group metal in group 14 of the periodic table. Tin shows chemical similarity to both neighboring group 14 elements, germanium and lead, like the two possible oxidation states +2 and +4...
or even plastic. When shot, the skirt will obdurate to fit the bore and provide a good seal, and engage the rifling, whereby imparting spin. In a smoothbore barrel, the skirt will still flare to provide a tight seal, but since there is no rifling, the pellet will not spin, and is less accurate. In most cases of this type, the solid head in the front and hollow skirt in back will work to prevent the pellet from tumbling. However, this is not always the case, and some ammo types of this nature will tumble in flight, and keyhole the target. You will know when this happens because the pellet will not leave a clean, round hole in the paper, but will instead, leave behind a keyhole looking silhouette.
Pellets are, by their very nature, designed to travel at subsonic speeds. High velocities can cause light pellets to overly deform, or even break apart in flight. The transition from supersonic to subsonic will cause almost all pellets to tumble. The closer a pellet gets to the speed of sound, the more unstable it becomes. A few companies have addressed this issue by manufacturing heavier than normal pellets for use in high powered air guns. These pellets travel at a reduced speed because of their heavier weight making them not only more accurate, but more lethal by increasing their kinetic energy.
Match shooting use
Match diabolo pellets are used for the 10 metre air rifle and 10 metre air pistol disciplines. These 4.5 mm (.177 in) caliber pellets have what is known as
wadcutterA wadcutter is a special-purpose bullet specially designed for shooting paper targets, usually at close range and at subsonic velocities typically under 800 ft/s . They are often used in handgun and airgun competitions...
heads, meaning the front is (nearly) flat, that leave clean round holes in paper targets for easy scoring. Match pellets are offered in tins, and more elaborate packaging's that avoid deformation and other damage that could impair their uniformity.
Match air gun shooters are encouraged to perform shooting group tests with their gun clamped in a fixed rest in order to establish which particular pellet type performs best for their air gun. To facilitate maximum performance out of various air guns the leading match pellet manufacturers produce pellets in graduated weight variants (the light/high speed variants are often marketed for air pistol use) and with graduated "head sizes", which means the pellets are offered with front diameters from 4.48 mm up to 4.52 mm.