Firearms Facts: DI vs Piston
This video compares Direct Impingement (DI) and Piston operating systems for firearms, primarily the AR-15. It explains how DI systems route gas directly to the bolt carrier, while piston systems use a separate rod. Piston systems generally run cleaner and cooler, especially when suppressed, but can be more complex and expensive. Historical examples like the AG-42 Ljungman (DI) and AK-47 (long-stroke piston) are discussed alongside modern short-stroke piston designs.









