Pellets come in a variety of calibers, shapes and weights. Standard pellet calibers are 0.177, 0.20, 0.22 and 0.25. Larger sized pellets can run from 0.357 to 0.50 caliber. The pellet caliber should correspond to the caliber of the gun they are intended to be used in. 0.177 and 0.20 caliber pellet guns are the most common. The smaller caliber, lighter pellet will generally travel at higher velocities. With certain air rifles, some smaller caliber pellets are known to travel faster than the speed of sound. However, the larger caliber heavier pellet will have more punch or knockdown power. The largest caliber air rifles or big bore air rifles are used for extreme air gun hunting. They are known to take down large targets such as deer or a large boar.
The general shape of a pellet is referred to as the “Diablo”, characterized by a larger head at the impact end sitting on a narrow waist, and tapering out at the base end like a skirt.. There are a number of variations to the “Diablo” shape. Each has distinct advantages and is selected according to the expected application.
The wadcutter is identified by a distinctive flat head. It is ideal for punching holes through paper or thin cardboard. It is typically used for target shooting or competitive shooting. Some of the more extreme match pellets are packed in individual holders so that the pellets do not touch. This is done to protect the surface and shape of the pellet, ensuring consistency and accuracy. Wadcutters perform better at shorter distances and are ideal at the typical competition distance of 10 meters. The shape of the wadcutter is not optimally aerodynamic. As a result, wadcutters start losing accuracy at about 15-20 meters.
ROUND NOSE (DOMED)
As the name implies round nose pellets have a rounded nose. The round nose offers the best combination of accuracy and knockdown power. Its aerodynamic design gives it accuracy out to longer ranges. It is an excellent all around choice for hunting, pest control or just plinking.
The pointed pellet features a pointed head, allowing for maximum penetration capability. It is most often selected for hunting. Pointed pellets have been known to be fairly accurate. Because of it's head shape, pointed pellets are not made to deliver high impact power. It is recommended for use in low to medium powered air guns.
The hollow point pellet has a hollowed out head which is designed to expand upon impact. It is most effective in higher powered air guns. Because of its head shape, the hollow point has good knockdown power. It is a good choice for pest control or hunting, particularly at closer ranges.
The pellet weight is designated in grains. One grain is equal to 0.06479891 grams. As a general rule of thumb, lighter weight pellets will travel faster than heavier pellets. However, lighter weight pellets are recommended for lower powered air guns, which do not have enough power to propel the heavier pellet in a straight line. Heavier pellets, on the other hand, should be used in higher powered air guns. Lighter pellets may result in unstable flight if used in a high powered gun.
Ideally, it is best to try different pellet brands, shapes and/or weights with a particular air gun and application to see what works best.