Archie to SAM: A Short Operational History of Ground-Based Air ...

FROM GUNS TO MISSILES
company delivered a .60-caliber version in 1950, and two years
later, a more advanced model appeared in three calibers: .60
mm, 20 mm, and 27 mm. The Air Force and Army adopted the
20 mm as the M61 Vulcan. Its six barrels were electrically
rotated and could fire at a maximum rate of 7,200 shots per
minute. The cannon was produced in a number of calibers.
Not only mounted aboard fixed- and rotary-wing aircraft, the
weapon was also adapted by the Navy (Phalanx) and initially
deployed in 1979 (fig. 37). The Army began development of its
version in 1964 and mounted the M61 on an M113 armored
personnel carrier as a daytime, clear-weather, air-defense
Figure 37. Vulcan Phalanx. The Navy fitted a number of its ships with
the fast-firing Vulcan Phalanx for close-in protection against aircraft.
(Reprinted from http://www.bb62museum.org/images/phalanx.jpc.)
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