The chain gun that traded recoil for a 1 hp motor

Wars & Conflicts · Published 16 October 2026 · Updated 25 October 2026 Swipe more like this →

In short: Most automatic weapons rely on the violent physics of gas or recoil to cycle their actions. The M242 Bushmaster rejects this mechanical chaos, instead using an electric motor and a roller chain to drive its bolt. This shift in engineering creates one of the most reliable autocannons in modern warfare.

Developed as part of a complex series of US Army programs in the 1970s, the M242 Bushmaster was born from the need to replace disappointing predecessors like the M139. While other projects were being rejected, Hughes Helicopters designed an externally-powered system that prioritized reliability. The core innovation is its chain-driven mechanism: a 1 hp DC motor drives a roller chain that moves the bolt back and forth to feed, load, fire, extract, and eject rounds from a metallic link belt.

This electric drive offers distinct tactical advantages over traditional gas-operated systems. Because it does not rely on recoil or gas pressure to cycle, it can operate even in the event of a misfire. The system features a dual-feed capability with a clutch mechanism, allowing gunners to switch between armor-piercing and high-explosive rounds seamlessly. It maintains a standard rate of fire of 200 rounds per minute, though it can be adjusted to a low rate of 100 rounds per minute or semi-automatic fire.

The weapon's success is reflected in its widespread adoption by over 15 nations and various branches of the US military. It serves as a primary armament for vehicles like the M2 Bradley and has been adapted into naval systems, such as the Mk 38 Mod 0. Its reliability is statistically significant, boasting a rating of 22,000 mean rounds between failure—a figure that far exceeds many comparable autocannons. Since 1990, it has undergone extensive upgrades, including chrome-lined barrels and enhanced receivers to maintain its status as a premier ground combat weapon.

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