Air guns are powered by either a spring-piston system, pneumatic mechanism or CO2 cartridge. They can have either a rifled or smoothbore barrel to fire pellets, whereas BBs can only be fired from smoothbore air guns. The range of a pellet gun depends on a number of factors.
Calibers
The three most common calibers available for air rifles are .177, .20 and .22. The standard pellet for most guns is the .177, which is the smallest and has the longest range; it is accurate at about 60 to 80 yards. The .20 is used in more expensive pellet guns, and is better for ranges under 60 yards. The biggest and heaviest pellet is the .22, which is accurate at about 45 to 50 yards.
Effects
Accuracy at long and short ranges also depends on trajectory. An air rifle can fire a pellet at a velocity as high as 1,200 feet per second, meaning the trajectory will be flatter and more accurate at long distances. Air pistols only fire at about 500 feet per second, and are much better for a short-range shot.
Types
There are four types of pellets. The Wadcutter pellet is best for target practice, while the round-nose pellet, the pointed pellet and the hollow-point pellet are best for hunting and pest control. The pellets are molded from soft lead and have an hourglass shape. This offers more stability in flight than a spherical steel or copper BB, which only has a range of up to 50 yards and is not as accurate.