Gasdruckladern

Gasdrucklader is a German term that refers to firearms that use the pressure of gases generated during firing to cycle the action. In a gas‑driven system, a small portion of the propellant gas is diverted from the barrel through a gas port in the barrel or receiver. The redirected gas forces a piston or directly the bolt carrier to move, which extracts and ejects the spent cartridge and chambers a new one. This mechanism allows semi‑automatic and fully automatic firearms to be self‑loading without the need for external power sources.

The type of gas system can be either long‑stroke or short‑stroke. In a long‑stroke system the gas piston remains attached to the bolt carrier and travels the full distance of the bolt cycle, as seen in the Heckler & Koch G36 or the SIG‑Sauer SG 550. Short‑stroke pistons release the gas pressure quickly and decouple from the bolt carrier, which can reduce recoil impulses and improve reliability, examples being the FN FAL and the M4 carbine. Some designs combine features of both types or employ a rotating bolt for additional locking strength.

Historically, the first practical gas‑operated rifles appeared in the late 19th and early 20th centuries, with the German Gewehr 41 and the later Gewehr 43 showing early use of the principle. The concept was refined after World War II, influencing many modern military rifles and personal defense weapons worldwide. Gasdrucklader are valued for their relatively low recoil, ability to handle high‑rate of fire, and compatibility with detachable magazines. However, they can be more complex to manufacture and maintain than simple bolt‑action or recoil‑operated firearms, and vulnerability to fouling from propellant residue can affect reliability in harsh environments.