Although not nearly as well
known as the quad mount halftracks, the Antiaircraft Artillery did employ
tracked motor carriages armed with the .50 caliber twin mount M33 turret. These halftracks were an intermediate step
in the evolution of self-propelled antiaircraft machine gun carriages.
The Army well understood
the necessity of mobile antiaircraft protection against low-level air attacks
on marching columns. Interwar and early World War II mobile implementations involved mounting single
water-cooled machine guns on a variety of vehicles from small
trucks to M2 halftracks. With the development of the M33 twin
gun power mount, the use of single fifties became somewhat archaic. An
initial experiment wed the M33 mount to a 6X6 truck, but the combination
of the twin turret on White's M3 Personnel Carrier halftrack quickly rose as the
obviously better option. This combination was dubbed the Multiple
Gun Motor Carriage M13 and was standardized in September 1942. A
substitute version, using the M5 halftrack manufactured by International
Harvester as a carriage, was designated
the M14. The M13 and M14 are difficult to distinguish, being very
similar in external appearance. Both models incorporated hinged
armor side and rear panels that folded down to allow the machine guns to
depress below horizontal.
White's Multiple Gun Motor Carriage M13 (above).
Compare to the photo of the IHC M14 (below).
The M13 was but the
beginning of a good idea. If two machine guns were good, four would
be better. Just a few short months after the standardization
of the M13/M14, the Antiaircraft Artillery Board would pair the M3
halftrack with the quad mount M45 turret, creating the legendary
halftrack, which promised a greater volume of fire. As the self-propelled quad mount vehicles rolled off
production lines, the M13 was relegated to the status of a substitute
Well camouflaged twin mount antiaircraft
halftrack somewhere in Italy.
Both machine guns fired simultaneously.
The M33 twin mount turret (shown without
shield) could traverse and elevate
at a rate of 60° per second.
quad mount M45 turret was very similar,
but used another style of switch box due
to its different electrical system.
Inside view of the M33 twin mount turret
used on the M13 halftracks. The handles connected to the switch box
moved the turret in azimuth and elevation. The triggers that fired
the machine guns were part of the handle assembly. The Navy
reflector sight is mounted between the hinged armor panels at the top of
In the Movies
Although not the most
famous of antiaircraft halftracks, a restored twin mount motor carriage made
brief cameos in the movie Saving Private Ryan. The
vehicle lends background atmosphere to a few early scenes that take
place post D-Day. An M16 may have been more historically
accurate for the film. However, since the important role of
Antiaircraft Artillery at Omaha Beach has been mostly overlooked,
the halftrack's inclusion in Ryan is appreciated.
Good use of camouflage netting and natural
vegetation render this M13 track nearly invisible to the enemy.
This crew is protecting a river crossing in
southern France - a common mission for Antiaircraft Artillery.
SOME PREDECESSORS OF THE ANTIAIRCRAFT
HALFTRACK MOTOR CARRIAGES
Prewar mobile antiaircraft protection was
simple. A light 4X4 truck mounting a water-cooled .50 caliber machine
thought sufficient. This photo of a
camouflaged truck has the door markings scratched out by an Army censor.
The .50 caliber machine gun is on an M2 mount.
Twin fifties on an M33 Maxon turret mounted
experimentally on a 6X6 truck at Aberdeen.
Although the Navy loved the 20mm Oerlikon, Army AAA
never embraced the weapon. However,
they were not
above trying out twin twenties on a
This test vehicle's power turret is
essentially the same as
that used for the .50 caliber machine guns.
The T1E2 test vehicle used an M2 halftrack
chassis as the carriage for the M33 twin fifty turret.
This arrangement was next tried on an M3 chassis as the experimental T1E4,
which became the M13.
Return to Weapons Index
Attachments and Assignments
AAA Unit Histories
Visit our Bookstore
About this Website
© Copyright 2009-2010 Brian L. Brooks