Page 38 - FAT 105 4.17 MOODLE

Figure 7: The unlocking step in the cycle of operations.

on caliber and model. The projectile will chamber pressure has dropped to a safe
then enter the forcing cone of the barrel level, the action may automatically begin
before engaging the rifling of the bore. to cycle or may be manually cycled. As
The projectile will then be forced from the action moves, camming surfaces or
the bore, out of the muzzle (Figure 6d). linkage will move the locking surfaces
of the barrel and bolt/breechblock/slide
• Unlocking – The unlocking step in the
away from each other, allowing the ac-
cycle of operations opens the chamber
tion to continue to travel through its
after firing. This can happen either man-
stroke. With revolvers, after the cartridge
ually or automatically depending on the
has fired, when the hammer is complete-
action being employed. Also, depending
ly de-cocked, the cylinder stop will move
on the action used, this may be an actual
out of the notch in the cylinder and un-
physical unlocking or just an “opening”
lock the chamber.
of the chamber.
Blowback actions that do not physically
Physically unlocking the chamber in-
lock the chamber (which are often semi-
volves the bolt, breech, or slide moving
automatic), unlock in a much simpler way.
out of alignment from the barrel/bar-
Once the chamber pressure has dropped
rel extension’s locking surfaces. When
to a safe level and the cartridge case has

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