well of the rotor (fig. 6-9). The insulated portion of the
contact cam in the firing contact assembly depresses
the firing pin cam in the breech-bolt assembly. This
moves the firing pin forward against the primer of the
round. The conductor portion of the contact cam makes
contact with the firing pin cam, which allows a firing
voltage to pass through the firing pin to fire the round.
The
breech-bolt
assembly
remains
locked
throughout the locking cam period until the projectile
leaves the barrel. After the projectile leaves the barrel,
the barrel pressure is reduced. The unlocking cam lifts
the bolt shaft, retracts the bolt-locking block, and
unlocks the bolt.
The main cam path guides the breech-bolt
assembly rearward. The empty case is removed from
the chamber by the extractor lip of the bolt assembly.
Then, the bolt assembly travels back along the rotor
tracks until the guide bar removes the empty case from
the bolt extractor lip and ejects it from the gun (fig.
6-10). To complete the cycle, the bolt assembly travels
along the rear cam dwell area and into position to
receive the next round.
REVIEW NUMBER 1 ANSWERS
A1.
The naval aircraft that carry the M61A1
20-mm automatic gun are the F-14 and
F/A-18.
A2.
When installed in naval aircraft, the M61A1
gun has a pilot selectable firing rate of 4,000
rounds per minute (GUN LOW) and 6,000
rounds per minute (GUN HIGH).
A3.
The primary parts of the M61A1 gun are the
barrels,
housing
assembly,
and
rotor
assembly.
A4.
The muzzle clamp assembly restrains in-
dividual barrel movement during firing.
A5.
The M61A1 gun has six rifled barrels that are
secured to the rotor by three rows of
interrupted locking lugs.
A6.
The recoil adapters have front mounting
points so the gun can be mounted in the
aircraft.
A7.
The rounds are guided into and out of the
extractor lip of the breech-bolt assemblies by
the guide bar.
A8.
The rotor tracks, rotor drive gear, and the
locking lugs to lock the barrels in place are
contained in the main body of the rotor
assembly.
A9.
The rear housing assembly and associated
parts provide the main cam path that controls
the movement of the breech-bolt assemblies.
6-8
Figure 6-9.—Breech-bolt assembly in firing cycle.
