Pre-charged pneumatic (PCP) airguns are usually filled by decanting from an air reservoir, such as a diving cylinder or by charging directly with a hand pump. Because of the need for cylinders or charging systems, PCP guns have higher initial costs but very low operating costs compared to CO2 guns. These guns are often used for hunting purposes in countries with restrictive firearms laws.
PCP guns have very low recoil and can fire as many as 500 shots per charge. The ready supply of gas, has allowed the development of semi-automatic PCP air guns. PCP guns are very popular in the UK and Europe because of their accuracy and ease of shooting. They are widely utilized in the sport of Field Target shooting,[10] and fitted with telescopic sights.
Earlier hand pumps for charging carried with them problems of fatigue (both human and mechanical), temperature warping, and condensation. None of those is beneficial to good shooting or the longevity of the rifle. Modern hand pumps have built-in air filtration systems and have overcome many of these problems. Using scuba-quality air decanted from a scuba cylinder also provides a clean, dry, high-pressure air supply that is consistent and available at low cost.