| Pellet rifles are at the air rifles that | | | | and the pellet is propelled to move |
| makes the use of pellets for firing. | | | | forward. This action requires only a |
| Spring piston pellet rifles | | | | fraction of second to take place. During |
| Spring piston is one of the operating | | | | this process, the air is adiabatically |
| mechanisms for the pellet rifles. The | | | | heated to several hundred degrees owing |
| spring piston air rifles are able to | | | | to the compression. The air expands |
| achieve muzzle velocities that can equal | | | | again after cooling. |
| the speed of sound. This can be achieved | | | | Pre charged pneumatic rifles (PCP) |
| from a single stroke of a cocking lever | | | | The PCP pellet rifles are used for |
| or the barrel itself. The power of the | | | | competitions and hunting. These are |
| rifle is related to the cocking stroke | | | | filled by charging from the hand pump |
| of the gun. Therefore high muzzle | | | | directly or by decanting from a |
| velocities require greater cocking | | | | reservoir of air like a diving cylinder. |
| effort. | | | | The initial cost of the PCP pellet |
| The operation of the spring piston | | | | rifles is high owing to the requirement |
| rifles depend on the spring loaded | | | | of charging systems and cylinders. But |
| piston of a coiled steel. This is | | | | the operating cost of these rifles is |
| contained within a compression chamber | | | | very low. |
| which is separately located from the | | | | Owing to the restrictive firearm laws, |
| barrel. | | | | these guns are used for hunting purposes |
| The assembly of the piston compresses | | | | outside United States. The recoil of |
| the spring when cocking of the gun takes | | | | PCP guns is very low. They fire 30 to |
| place. The spring is compressed until a | | | | 500 shots per charge. The development of |
| small hook present on the rear of the | | | | semi automatic PCP pellet rifles has |
| piston engages the sear. This sear is | | | | become possible due to the ready supply |
| released when the trigger is pulled and | | | | of gas. PCP pellet rifles are very |
| the spring is decompressed. Thus the | | | | popular in Europe and UK because of |
| piston is pushed forward and the air | | | | their ease of shooting and accuracy. |
| behind the chamber is compressed | | | | They can be fitted with telescopic |
| directly behind the pellet. | | | | sights and are widely utilized in the |
| After the air pressure increases enough | | | | field target shooting sport. When fitted |
| to overcome any barrel restriction or | | | | with silencer or sound moderator, these |
| any static friction that holds the | | | | rifles can be made quiet. |
| pellet, the column of the air expands | | | | |