Pellet (air gun)

It consists of a solid front portion called the head, which can have a flat ("wadcutter"), hemispherical ("round nose"), hollow point or conical ("pointed") front end profile, and a thin-walled funnel-shaped hollow rear portion called the skirt, joined by an hourglass-looking narrow mid-section known as the waist, giving the whole pellet the shape of a diabolo.

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 air as is possible.

[citation needed] The thin hollow skirt is made of a malleable material, usually lead, although non-toxic alternatives are available that use tin or even plastic.

During shooting, the skirt flares out and obturates the bore when pressure builds up behind it to provide a good seal that allows efficient pellet acceleration, and engages the rifling whereby imparting spin.

This is a problem for high-powered "magnum" break-barrel and pre-charged pneumatic air rifles, which are capable of pushing lighter pellets beyond the sound barrier.

[citation needed] The heavier weight of these pellets ensures lower muzzle velocities, resulting in less chance of tumbling and more overall accuracy.

Their weight also makes them sectionally denser and less susceptible to wind deviation and drag deceleration, and thus imparts better external and terminal ballistic performance.

However, lead-free pellets typically have a lower ballistic coefficient (BC), which results in more wind-drift, and reduced velocity at longer distances.

Lead-free pellets are offered by all major manufacturers, including RWS, Gamo, H&N Sport, Predator International, JSB, Crosman, SIG Sauer, and others.

Since the soft lead alloy is prone to strongly deform when striking a bullet catcher, it rapidly loses its kinetic energy and will not easily bounce off.

For this reason, many shooters use lead-free match pellets, produced by H&N Sport, Predator International, JSB, RWS, Olympia Shot, Gamo, or Daisy.

[7] Unbatched ammunition, especially if the air gun is not regularly cleaned, is generally thought to be capable of only 8.0 mm (0.315 in) diameter group sizes.