FM 23-45 Basic Field Manual
1
BASIC FIELD MANUAL
BROWING MACHINE GUN, CALIBER .30, HB M1919A4
GROUND
(The matter contained herein supersedes chapter 1, part seven, Basic Field Manual,
July 1, 1937.)
MECHANICAL TRAINING
Paragraphs
S
ECTION I. Description 1-8
II. Disassembling, assembling and changing parts 9-21
III. Care and cleaning 22-26
IV. Mechanical functioning 27-39
V. Stoppages and immediate action 40-42
VI. Tripod mounting 43-44
VII. Accessories 45-52
VIII. Fire control instruments 53-54
IX. Individual safety precautions 55-58
X. Ammunition 59-66
S
ECTION I
DESCRIPTION
■1. P
RINCIPLE OF OPERATION. — The machine gun, caliber .30, M1919A4, is recoil
operated, belt fed, and air cooled. In recoil operation the rearward force of the
expanding powder gas (kick) furnishes the operating energy. The moving parts, while
locked together at the moment of the explosion, are left free within the receiver to be
forced to the rear by the recoil. This movement is controlled by means of various
springs, cams, and levers, and is utilized to perform the necessary mechanical
operations of unlocking the breech, extraction and ejection of the empty case, and
feeding in of the new round, as well as cocking, locking, and firing the mechanism. (See
fig. 1.) The receiver mechanism is for all practical purposes the receiver of the
Browning machine gun, M1917.
■2. C
OOLING SYSTEM. — The machine gun, caliber .30 M1919A4, is provided with a
heavy barrel which is exposed to the air. This factor serves to keep the gun at operating
temperatures under normal conditions, i.e., at the rate of about 60 rounds per minute
for about 30 minutes.
