What is the defining feature of the glock action?

The defining feature of the Glock action is its striker-fire mechanism. In a Glock, the firing pin, or striker, is partially cocked as the slide moves to the rear, and is fully cocked just before firing. This system eliminates the need for a hammer, which is present in more traditional, hammer-fired firearms.

The striker-fire action allows for a consistent trigger pull with every shot, enhancing the ease of use and accuracy for the shooter. It also contributes to the pistol's reliability and simplicity, as there are fewer moving parts compared to hammer-fired systems. This design has become very popular in modern handguns due to its effectiveness and user-friendly attributes.

In contrast, other options like the hammer-fired system indicate firearms that utilize an external or internal hammer mechanism, the single action trigger refers to firearms that fire only once per pull of the trigger without additional caching of the firing mechanism, and the revolving cylinder is characteristic of revolvers but does not pertain to the design and operation of Glock handguns. Ultimately, the striker-fire action is what sets Glock pistols apart in the realm of semi-automatic firearms.