What is one of the safety mechanisms in the weapon?

The decocking/safety lever is an essential safety mechanism in the M9 Service Pistol. This feature allows the shooter to safely lower the hammer on a live round without firing the weapon. When engaged, the decocking function moves the hammer to a decocked position, preventing accidental discharge while also ensuring the firearm remains ready for use.

This mechanism is particularly important in situations where the shooter may need to carry the firearm with a round in the chamber but wants to minimize the risk of unintentional firing. By utilizing the decocking lever, the user can safely prepare the weapon for use or transport it without compromising safety.

In contrast, other mechanisms listed do not serve the same function. For instance, while the double action trigger can enhance the trigger pull, it does not provide a direct safety function like the decocking/safety lever. Similarly, the rimfire bolt and automatic ejector, although important parts of firearm operation, do not contribute to the safety mechanisms designed to prevent accidental discharge when handling the pistol.