Pre-Charged Pneumatic (PCP)
The majority of these pistols are dedicated to match competitions, which are all shot at 10m with 0.177 pellets. All the sights are open, and telescopic sights are not allowed. Match pistols can be priced from basic beginner models at about £230 to expensive models (£1600+) for national and international events. Second-hand prices are often available.
Spring
There is a wide variety of spring-powered (metal-coil) pistols. The first models were pre-1930, and now current models are up to date. Some people collect. Others will attach telescopic sights, adjust triggers, change grips, etc. The quality and price vary from ~£50 to ~£ 400. The accuracy is limited due to the recoil, but it is an enjoyable experience.
Gas Ram
Similar to the above, design improvements have led to spring pistols that now use a single compression stroke to fill a cylinder. The pistols have a much smoother recoil on firing. However, the recoil is still present. Nice to use. There are only a small number of these pistols. Some manufacturers have simply moved to the CO2 type air pistols, see later.
CO2
The pistols are mainly based on replicas of real revolvers and automatic pistols. A small CO2 steel canister holds 12g of liquefied carbon dioxide. When the trigger is pulled, a small amount of gas is vented and propels the pellet.
Depending on the pistol, a CO2 canister provides about 40 to 80 shots. You need to take care and follow the instructions when replacing the canister. BBs are not as accurate as the 0.177 pellets in some guns.