Paint grenades

Paintball is an equipment intensive sport and in order to safely conduct a game, every player requires a marker with propellant to fire the paint, a mask to protect the eyes and face, paintballs, and a loader to hold them. To ensure safety off the playing field, a barrel sock or plug for the marker is also compulsory.

Depending on type of play, additional equipment can include gloves, a pack designed to comfortably carry pods containing extra paintballs, and a squeegee or swab for cleaning out the barrel in case a paintball breaks. Players may also elect to wear padding or armor in order to reduce the impact of incoming paintballs.

A paintball marker is the primary piece of equipment used in paintball to tag an opposing player. An expanding gas (usually carbon dioxide or high-pressure air) forces a paintball through the barrel at a muzzle velocity of approximately 90 m/s (300 ft/s). This velocity is sufficient for most paintballs to break upon impact at a distance, but not so fast as to cause tissue damage beyond mild bruising. Nearly every commercial field has, and strictly enforces, a rule limiting the muzzle velocity of a paintball at or below 90 m/s (300 ft/s). Speeds above 250 are typically needed to ensure the paintball breaks on impact; the field limit is thus usually somewhere in between, often 260-280fps. The technology used to design and build paintball markers has advanced over time, beginning with the original "Nel-Spot" bolt-action pistols, progressing to pump-action markers, then to semi-automatic mechanical markers, and finally culminating in the electropneumatic paintball marker.

In mechanical designs, the trigger manipulates a sear, which is holding a hammer, ram, or sealed gas chamber in its resting state. Pulling the trigger releases the sear, allowing the marker's action to cycle. There are a variety of mechanical designs, the most common being the "blow-back" marker, which utilizes a spring-loaded ram released by the sear to open a pin valve; the pressurized gas released through the valve is directed through the bolt to fire the marker, and also pushes the ram back where it is caught again by the sear, resetting the action for the next shot. There are other systems that saw success in earlier days of the sport, such as blow-forward (AGD Automag) and pneumatically actuated recocking (WorrGames Autococker); elements of these designs were carried forward into modern electropneumatic designs but the original examples of these mechanisms are rarely seen today.

...
Wikipedia