The plunger operates with a spring system, a cocking lever, a cartridge of compressed air or CO2.
Widespread, solid and inexpensive, the spring system is characterized by a piston mounted behind the barrel and a spring whose force defines the power of the gun. A lever makes it possible to compress the spring and to move the piston back: this action is commonly called "arming of the weapon". The pressure exerted releases the piston which then expels compressed air into the chamber where the projectile has been deposited.
The compressed air gun is not equipped with a spring to move the piston. It is equipped with a compression chamber placed just before the chamber containing the projectile.
- The cocking lever model is characterized by a cocking lever which pre-compresses the air in the compression chamber and which acts directly on the piston. The pressure exerted on the trigger shank makes it possible to release a valve allowing the gas to relax in the air and then to propel the projectile.
- The cartridge model does not use the cocking lever but a reloadable metal cartridge that is placed under the barrel of the weapon. Less solid, it is quieter and more accurate than spring and piston pistols.
To propel the projectile, the CO2 gun does not use a cocking lever, piston, or spring but a cartridge of liquid CO2. Disposable or rechargeable, the cartridge is simply placed at a specific location and its tip is automatically drilled when screwed.
So choose your plunger according to the power you want to achieve, and the ease you would like to have.