What is the minimum free length of the M9 pistol recoil spring?

The minimum free length of the M9 pistol recoil spring is essential for ensuring the firearm operates correctly. A recoil spring that is too short won't provide the necessary force to return the slide to its forward position after firing, which can lead to malfunctions. Specifically, the M9 requires a recoil spring free length of 5 inches to maintain proper cycling of the action, allowing the pistol to function reliably under normal operating conditions.

This specification is critical for both operational effectiveness and for maintaining the weapon's longevity, as using a spring that does not meet this length can lead to increased wear or damage over time. Understanding this dimension is part of the comprehensive knowledge required for personnel involved in the maintenance and training of weapons to ensure optimal performance and safety.