Gasdruckläufe

Gasdruckläufe, also known as gas-operated actions or gas systems, are a common mechanism found in semi-automatic firearms. This system utilizes the expanding gases produced when a projectile is fired to cycle the firearm's action, automatically ejecting the spent casing and chambering a new round. This process allows for rapid follow-up shots without manual manipulation of the bolt.

The core principle involves tapping a small amount of propellant gas from the barrel, typically near the muzzle, and directing it through a gas port. This gas then travels through a gas tube or a similar conduit to a gas cylinder located near the receiver or bolt carrier. The pressurized gas acts upon a gas piston, which is connected to the bolt carrier. The force of the gas pushes the piston rearward, which in turn drives the bolt carrier back, unlocking the bolt, extracting and ejecting the spent cartridge, and compressing the return spring. As the bolt carrier moves forward, driven by the return spring, it strips a new cartridge from the magazine and chambers it, locking the action for the next shot.

Variations exist in gas-operated systems. Long-stroke systems, like those found in Kalashnikov-pattern rifles, feature a piston that moves the full length of the gas tube. Short-stroke systems, common in many AR-15 style rifles, have a piston that travels a shorter distance, imparting impulse to a separate carrier. The design and implementation of gas pressure regulation are crucial for reliable functioning across different ammunition types and environmental conditions.