Pellet (air gun)

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A pellet is a small, non-spherical projectile fired from an air gun. Air guns use much lower pressures than firearms, so pellets are designed to work with gentler forces.

The most common pellet shape is the diabolo, which has a solid front part called the head and a hollow rear part called the skirt, joined by a narrow waist. The head touches the rifling to stay centered, while the soft, flared skirt seals the bore as pressure builds behind it and helps the pellet spin in rifled barrels. In smoothbore barrels, there is no spin, but the skirt still helps seal the bore and stabilize the shot, though it’s less accurate.

Pellets are usually designed to travel at subsonic speeds. If a pellet goes too fast, especially lighter ones, it can deform, break apart, or tumble in flight. This can cause the pellet to hit sideways (keyholing) and miss the target. Heavier pellets tend to be more stable at higher speeds.

There are different pellet types. Diabolo pellets remain the most common. Slug pellets are heavier and more rounded, with no skirt, and they rely on rifling for stability. Lead-free pellets use metals like zinc, tin, copper, or combinations; they’re lighter, can reach higher speeds, and drift more in wind, but often don’t penetrate as deeply as lead. Lead pellets are softer and may fragment or mushroom on impact, which hunters sometimes prefer, though many shooters use lead-free versions for environmental reasons. Pellets come in various weights, especially in competition, and different head sizes to fit different barrels.

BB guns historically used round lead or steel balls in smaller calibers and are now often seen with similar calibers as pellet guns. In ballistics and competition, match pellets (4.5 mm/.177 caliber) often have wadcutter heads that leave clean round holes in targets, making scoring easier. They’re usually soft lead or lead-free and are tested in batches to find the best match for a specific gun.

Dieseling is when lubricant in the gun lights off from compression, adding extra velocity and a loud report. To avoid it, shooters use non-flammable silicone-based lubricants.

In short, pellets are carefully shaped and weighted to balance speed, stability, and accuracy in air guns, with options tailored for lead or lead-free materials, rifled or smoothbore barrels, and target shooting or hunting.