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

The minimum free length of the M9 pistol recoil spring is 5 inches. This measurement is important because it ensures that the recoil spring has sufficient tension when the pistol cycles, allowing it to effectively manage the energy produced during firing. A recoil spring that is too short may not provide adequate resistance, potentially leading to malfunctions as the slide may not return to battery properly. Maintaining the correct free length also contributes to the overall reliability and longevity of the firearm, as the spring is designed to operate optimally within specified lengths. Understanding this specification is key for proper maintenance and troubleshooting within the context of Combat Arms Training and Maintenance.