July-August - Air Defense Artillery School

The .50 Machine Gun As
Subcaliber H40"*
This article describes the use of the Browning machine
gun caliber .50 water cooled. as subcaliber for the 40mm
automatic gun, 1\ 11, both for the Case I and Case III methods
of firing. A short note is added to cover the possible
use of other weapons for subcaliber purposes.
This subcaliber weapon is intended to serve several purposes.
It is intended to compensate for the lack of 40mm
practice ammunition, a lack which has necessitated the
employment in practice of expensive HE ammunition that
would otherwise have gone to troops in the field. In addition
to saving ammunition, the use of the subcaliber mount
\vill save wear and tear on the larger caliber guns and barrels
that are needed for actual combat. Furthennore, the
bursts from 40mm HE ammunition have often cut short
towino missions bv destrovin£! tar£!ets. Caliber.50 ammub
,/" L~ ........
nition will have this effect only under the most exceptional
*Prepared at the Antiaircraft Artillery School, Camp Davis,
tg-2;T~i-11-
7"
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Figure 1
circumstances. For these reasons. subcaliber firino \
permit more extensive and economical firing during
liminan' _ trainino. 0 I\l0reover. it will permit more e£fec
training during this period. Experience has shown t
tracking will be more effective and a crew's confidence
creased when its first firing is conducted without the d'
tracting noise and flash of normal 40mm fire. Gre
crews have regularly obtained more Ilits ming tl'is s
caliber mOH/lt. Crews must, however, become used to t
noise and flash. For this reason, no subcaliber firing will
a satisfactory substitute for actual
the later st;ges of training, and
fire of the 40mm
no troops should
duri
be eotf
sidered fully trained who have not had considerable e
perience firing actual 40mm ammunition at the appropri~
targets. The caliber .50 machine gun was chosen as l~
subcaliber weapon for the 40mm because, among weaP01
for which tracer ammunition was available in quantity. )I
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