Page 127 - FAT 105 4.17 MOODLE

allowing you to try to fire a cartridge that failed
Single- and Double-
to ignite from the first impact. The hammer-
fired system also has the advantage of being
more robust and heavy duty. Action and Single-
The striker-fired system has the advantage of and Two-Stage Trigger
being more compact and simple. This is espe-
cially important with semi-automatic pistols,
where a thin slide and low bore axis are con- SINGLE- AND DOUBLE-
cerned. The system also has the advantage of ACTION TRIGGERS
having a faster lock time. Lock time is the time
it takes from the moment the trigger releases
Depending on the system, the trigger motion
the hammer/striker to the point where the fir-
itself will perform multiple actions through
ing pin/striker contacts the primer and initi-
various stages of travel. Regardless of whether
ates ignition. Even though this happens within
the system is hammer- or striker-fired, the trig-
milliseconds, any disruption in the firearm and
ger may perform various actions with different
sights at this time will cause the point of aim
stages. First, we will discuss trigger actions.
and point of impact to deviate. Reducing the
There are two trigger action types: single- or
lock time will reduce the possibility of devia-
double-action. Single-action is so named be-
tion in the intended trajectory. By design, the
cause of the fact that the trigger only performs
mechanics of the striker-fired system allow it to
one action: when the trigger is pressed, it will
be much faster than the hammer-fired system,
release the hammer/striker (either directly or
although aftermarket parts can be used to speed
through some other mechanical means). This
up both systems.
means the hammer/striker must be manually
cocked (via hammer or through charging the

Figure 5: Single-action trigger function.

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