Page 100 - FAT 105 4.17 MOODLE

Figure 21a (top) & 21b: A falling locking
block pistol (Beretta 92).

short recoil action chamber locks continue to move rearward. As the
similarly to the bolt-action design. slide continues rearward, it will extract
and eject the empty case and cock the
The rotating barrel action relies on a
hammer/striker. On its forward stroke,
barrel with a helical track or channel
the slide will strip a fresh round from
machined into it and a lug located in
the magazine and feed and seat it into
the frame. The barrel also contains in-
the chamber. The slide will contact the
tegral lugs that correspond with lugs
barrel and drive it forward. The lug
in the slide. During discharge, the
on the frame will force the barrel to
pressure inside the chamber will cause
rotate again, aligning the locking lugs
the locking surfaces to hold it closed
and locking the chamber.
until the bullet has exited the bore
and pressure has dropped. The barrel Like the falling locking block ac-
will begin to move backward, driving tion, the rotating barrel action is very
the slide with it. old, with models ranging from over
120 years old. The original patent on
The lug on the frame cams against
the rotating barrel lock-up system
the channel of the barrel and forces
was awarded to John M. Browning
it to rotate. As the barrel rotates, the
for the 1897 Rotating Barrel Pistol.
lugs on the barrel and slide will move
In 1912, Steyr introduced the 1912,
past each other, allowing the slide to
which used the rotating barrel system.

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