pistonandbarrel

Piston and barrel is a term used to describe two fundamental components found in many mechanical systems, most notably firearms and certain gas- or hydraulic-powered devices. The combination refers to a piston that moves in a bore or cylinder and a barrel, which is the hollow tube that contains or guides the moving elements or the resulting projectile and gases.

The piston is a solid or hollow cylindrical component that slides linearly within a chamber. It is usually sealed with rings to maintain pressure and prevent leakage. The piston converts pressure from a fluid or gas into linear motion and can transmit that motion to other parts of a mechanism, such as a bolt, valve, or connecting rod.

The barrel is the cylindrical passage that houses the moving parts’ interaction with gases or projectiles. In firearms, the barrel directs the path of a bullet and often contains rifling to stabilize the projectile. In pneumatic or hydraulic devices, a barrel or bore serves as the route through which pressurized fluid or gas acts on the piston.

In practice, a piston and barrel pair is used to convert high-pressure gas into mechanical work. In firearms with gas-operated actions, expanding propellant gases push a piston that cycles the action while the barrel guides the projectile. In other applications, pistons within a barrel-like housing act as actuators, valves, or power cylinders. The design and materials vary by application, but the basic principle remains the same: controlled linear motion produced within a cylindrical bore.

See also: piston, barrel (gun), gas piston, cylinder, rotary or linear actuators.