United States. Army. Ordnance Dept.

Handbook of artillery : including mobile, anti-aircraft and trench matériel online

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counterrecoil. The piston is fitted with four holes for the passage
of oil during recoil. This oil is allowed to pass through two parts
of the piston; first, through the hollow portion of the piston rod, and
second, through the holes in the piston head. The oil passages in
the piston head are closed by the piston valve. The valve is held
against the front face of the piston by a spring, closing the oil holes
in the head during the counterrecoil stroke, thus slowing up the for-
ward motion of the gun. The counterrecoil buffer is screwed into
the front cylinder cap and eases the movement of the gun into
battery, thus preventing excessive shock. The capacity of recoil
cylinder is 2.75 pints and the extreme travel of piston is 11 inches.


The mount may be used either in the form of a tripod or with the
axle and wheels attached. n the former case a front leg having a
float adjustable to two heights at its lower end is used to support the
front end of the mount, and the spread trails in rear equipped with
spades form the other points of support. n the case of the wheels
being used, the front leg is swung up and secured, and both trails
are spread out to support the rear.

The pintle, or gun mount, is in the form of a yoke, the upper end
being fitted to receive the cradle trunnions. Each trail head is
equipped with lugs which pivot on bearing surfaces in the lower end
of the pintle. The trails, when spread, are kept in position by a
removable transom, which also serves as a seat for the gunner.

A Y-shaped frame, pivoted and secured to the pintle at its upper
and lower ends, extends to the rear in the form of a fork and engages
the nut housing on the traversing screw. The nut is turned in its
housing by a small handwheel attached thereto, w^hich causes the


nut and housing to move along the screw, thereby traversing the
gun. The screw is pivoted in the left trail and moves in and out
through a bushing pivoted in the right trail when the trails are being
spread or closed. When the trails are to be closed, the gun is trav-
ersed to the extreme right.

The elevating mechanism is located on the frame in front of the
traversing mechanism. A screw fitting into a nut pivoted in the
frame is raised and lowered by a handwheel attached to its upper end.
Above the elevating handwheel is a hook engaging a pin fitted to
the underside of the cradle, thus the rear end of gun is secured to
the trail and the elevation accomplished when the cradle is mounted
in the trunnion bearings.

A conical sheet metal flash hider is secured to the muzzle of the
gun. Some of these carriages are equipped with an armor plate
shield, suitably reinforced by stiff eners. The shield consists of three
plates hinged together, and is mainly employed to protect the gunners
from shrapnel and flying fragments.


The gun is provided with a telescopic sight for use in direct fire
and a quadrant sight for indirect or masked |ire, either of which is
mounted on the left side of the gun and in a bracket which is part of
the striker rod housing.

The wheels are 37.75 inches in diameter and have steel tires 1.875
inches in width.

The ammunition is of the fixed type having a steel projectile weigh-
ing 1.097 pounds containing high explosive, and detonated by a
base percussion fuse. A complete round of ammunition weighs 1.47
pounds and is composed of projectile, brass case, primer, and
powder charge.




The 37-millimeter gun limber (of the machine gun ammunition
wagon type) is essentially a frame resting on two shafts having a
movable bolt and rear fittings by means of which it can be joined
to the gun mount.

The limber carries 14 ammunition boxes, each containing 16 car-
tridges packed in a fiber packing strip. There are also provided
2 wooden boxes for carrying spare parts, tools, accessories, etc.


The 1-pounder semiautomatic gun and carriage was primarily in-
tended for landing purposes, but it has been used in trench warfare
and to accompany infantry troops. This equipment is well adapted
to the latter uses, due to the fact that its weight is such, as to permit
it to be readily transported from place to place by man power.

The gun is made of nickel steel, with the gun body and breech end
being forged in one piece. The breech mechanism is of the Bethle-
hem semiautomatic type in which the breech is opened, the case
ejected, and the firing pin cocked on counterrecoil. The block is
closed by a spring which is compressed during counterrecoil and
held in that position by the extractor until tripped by the insertion
of another round.

The carriage is of the long recoil type and consists essentially of a
cradle, pivot yoke, trail, wheels, and axle. The cradle supports the
gun, forms a housing for the recoil mechanism, and is itself supported
by trunnions bearing on the pivot yoke. The recoil mechanism is
located above the gun and consists of a hydraulic cylinder and
counterrecoil springs. No elevating and traversing mechanisms are
provided as the laying can be readily accomplished by means of a
shoulder guard and grip.

Open sights are furnished and a bullet proof armor plate shield
affords protection for the cannonneers.

Fixed ammunition is used, and is packed for transportation in steel
boxes containing 60 rounds each. A hand cart for carrying four boxes,
240 rounds, is issued, the front and lid of this cart, being bullet proof.

Weights, dimensions, and ballistics.

Length of gun inches. . 68. 2

Length of rifling do 61. 7

Number of grooves 12

Muzzle velocity feet per second . . 2, 100

Maximum range yards. . 4, 100

Weight of charge pounds. . . 16

Weight of projectile do 1. 07

Weight of complete round do . . -. . 1.5

Weight of gun and breech mechanism do 173

Breech block Vertical sliding, semiautomatic . .

Recoil (constant) inches . . 10

Weight of carriage in battery position pounds. . 800

Range of elevation degrees. . 5 to +15

Amount of traverse , do 45

Width of track inches . . 35

Line of sight Dependent. .

Height of axis of bore inches . . 29

Diameter of wheels do . 42






The 2.95-inch Vickers-Maxim mountain gun materiel, is of Vickers
design and American and British manufacture. This materiel is
intended for transportation by pack animals; for this reason it is a
light, compact weapon, separating very quickly and easily into four
loads for packing.

The cradle is carried as one load, the wheels and axles as another,
the trail another, and the gun as the fourth. Four other pack animals
carry the pioneer tools, blacksmith's tools, supply chest, and signal
tools, respectively. Additional pack animals are employed to carry
the ammunition for the battery. Suitable pack frames with all the
necessary attachments are provided for holding the load compactly
and in proper place on the animal.

Weights, dimensions, and ballistics.

Caliber . . .inches . . 2. 953

Length of gun do 35. 85

Weight of gun, including breech mechanism pounds . . 236

Rifling uniform, 1 turn in 25 calibers, right -hand twist.

Weight of projectile do 12$

Weight of powder charge ounces . . 8

Muzzle velocity feet per second - - 920

Maximum range .. yards . . 4, 825

Length of recoil of gun inches . . 14

Height of axis of gun above ground do 26

Maximum angle of elevation degrees . . 27

Maximum angle of depression '. do .... 10

Amount of traverse of gun on carriage do ....

Diameter of wheels inches . . 36

Width of track do 32

Weight of carriage only pounds . . 595

Weight of gun and carriage do .... 830

The gun barrel is a one-piece steel forging, cylindrical in form.
On either side of the breech end two lugs are provided to which the
piston rods are secured when the gun is mounted in the cradle. For-
ward of these lugs is a finished surface of uniform diameter which
constitutes a bearing for the gun. This surface is supplemented at
the forward end of the gun by two collars of equal diameter, thereby
insuring a firm bearing for the gun in the cradle, either in recoil or
in battery. At the bottom of the barrel is a guide which slides in a



corresponding groove in the cradle, thus keeping the gun in proper
position and preventing it from turning when in action.

The breech mechanism is of the interrupted-screw type. A handle
which swings from left to right turns and swings the block clear with

one motion. The firing pin is operated by means of a trigger which
is pulled by the firing lanyard. A safety device is incorporated to
prevent firing when the breech is not closed. The breech is equipped
with an extractor which ejects the empty cartridge case after firing.


The recoil mechanism is of the hydrospring type. It is known as
the short-recoil type in which the gun is permitted. a length of recoil
upon the carriage, sufficient to diminish the movement of the carriage
on the ground but not sufficient to render the carriage stable. To




retard the movement of the carriage on the ground the wheels are
locked by means of " brake ropes/' which lock the wheels to the trail.
Two buffer cylinders, one on each side of the gun, are bored in the
cradle casting. They contain both the recoil and counterrecoil
mechanism. The cylinders are connected at the rear by a by-pass
which keeps the oil pressure equal in the two cylinders. Throttling


is obtained by grooves of varying width in the cylinder liners. The
piston rods are attached to the gun by means of interrupted screws,
which permit quick removal for transportation.

The counterrecoil mechanism consists merely of springs wound
around the piston rods, which are compressed on firing and which
return the gun into battery.


The cradle is a bronze casting comprising three parallel cylinders.
The central cylinder supports the gun from the breech to within a few
inches of the muzzle. The other two, as before stated, accommodate
the recoil mechanism. In place of trunnions there are two lugs
underneath the cradle through which passes the cradle axis bolt, by
means of which the cradle is secured to the trail. This bolt is pro-
vided with a handle and suitable catch for quick removal when
disassembling for packing. The cradle also carries the sight bracket


and has a plane surface on top, on which the gunner's quadrant may
be used.

The elevating gear consists of a quadrant with a worm wheel
segment thereon operated through suitable gearing by a handwheel
on the left side of the trail. A bolt for quick release of the elevating

pi 5 fan lock.


mechanism from the cradle is provided. Elevations from 10 degrees
depression to 27 degrees elevation may be obtained.

No traversing mechanism is provided, and transverse must there-
fore be obtained by swinging the trail.

e/sra//** /breech


The trail consists of two steel side plates connected by crosspieces
and transoms. The front crosspiece contains bearings for the axle,
cradle axis bolt, and elevating gear. A shoe at the rear end of the
trail is fitted with a "scraper," which in reality is a short spade. It
is also provided with a socket for the handspike.
18322820 5


The axle is a solid cylindrical bar with flats cut on two sides for
securing it in the front crosspiece of the trail. It is quickly removable
for packing and is carried on the same pack animal as the wheels.
The wheels are 36 inches in diameter and are steel tired.

Sighting is accomplished by means of the sight, model of 1912,
combined with either an open sight or the panoramic sight.

The sight shank is a steel arc which can be moved up and down in
elevation by means of a scroll gear. A range strip on the rear face of
the arc is graduated in 50-yard divisions up to the maximum range
of the piece.

Combined with the sight is a graduated level which serves the same
purpose as the range quadrant used on the 3-inch equipment and other
materiel of that type. By this means the piece is laid for elevation.

The sight is mounted on the left side of the cradle. By ha\ ing the
quadrant level and sight thus combined one man can lay for both
elevation and direction.

The ammunition used is of the fixed type, consisting of the steel
high explosive and shrapnel shells, each weighing 12 J pounds. Each
animal carries two chests containing five rounds each.


The United States model 1916, 75-millimeter field gun is an adap-
tation from the United States 3-inch field gun, model 1916, arranged
with a split trail and having greater traverse and greater elevation
than either the French or British models of this caliber.

The 75-millimeter field gun constitutes the light artillery or rapid
mobile field artillery of the Army. The caliber of the piece is about
as large as ready horse-drawn mobility will permit. The caliber is


equivalent to 2.95 inches, and was adopted by the French and by
the Italians, while the United States had adopted the caliber of
3-inch and Great Britain a caliber of 3.3-inch, which is the caliber of
their 18-pounder. The German caliber was 77 millimeters, equivalent
to 3.03 inches. The points of excellence obtained from these types
are accuracy, long range, rapidity of fire, ease of transportation, and
smooth and reliable functioning.

As the range depends not only on the power of the gun and on the
design of the ammunition but on the elevation provided for, and




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as the horizontal afc which could be covered by a gun with a single
setting of its trail is governed by the permissible traverse, great
attention was given to the mechanical features covering the vertical
and horizontal limits of the gun laying, as well as to the smooth and
reliable functioning of the piece. Of the above models, the French
model is credited with functioning most perfectly, but the United
States completed a new carriage which permits very high elevation
of the gun and wide traverse. Due to the permissible elevation, the
American piece outranges the French, although the French gun has a
greater muzzle velocity.

Roughly, the weight of the piece, including the carriage and limber,
is about 4,600 pounds, which in general corresponds with the horse-
drawn draft limitation over rough ground of 765 pounds per animal,


calling for six horses to the piece, although four horses are frequently
employed over level or hard ground.

The introduction of motor tractors has altered the draft problem,
but there still remains the question of facility in handling the piece
by man power after battery position has been reached. As illus-
trative of this it may be mentioned that the weight at the end of a
75-millimeter gun carriage trail is in the vicinity of only 100 pounds.
The trails can be readily unlimbered and spaded into position or its
position changed by man power within a few moments, while to
unlimber and spade into position or to change the position of the
trail of a 155-millimeter gun requires the use of jacks and a con-
siderable expenditure of time.

Rapidity in moving a fieldpiece from point to point, where railroad
transportation is not available, is not entirely a matter of the speed
of the tractor, for likelihood 6f damage to the materiel when trans-
ported at high speed on its own wheels must also be considered.


The dimensions and weight of the 75-millimeter piece permit of its
being placed on a rubber-tired trailer, which allows of its being
transported at high speed behind a motor vehicle.

The movement of the light artillery is of utmost importance, and the
75-millimeter field gun may be considered as a gun of first rank, for
it constituted the light artillery of the military powers. This weapon
is accurate, has a range up to 6 or 7 miles, is suitable for the projection
of high explosives, shrapnel, incendiary, smoke, asphyxiating, tear,
tracer, illuminating, terrorizing, and chain projectiles, and is adaptable
for barrage fire, destruction of personnel, tearing away of wire entangle-
ments, destruction of fair-sized obstacles, and to some extent the
destruction or protection of lines of communication. The indications
are that a slightly larger caliber will supplant this caliber in order to
obtain longer range and greater destructive force and either motoriza-
tion or direct mounting on self-propelled caterpillars may affect the


adoption of a new caliber, for mobility and rapidity and ease of
handling are features of importance in this branch of the field artillery.

Weights, dimensions, and 'ballistics.

Weight of gun and breech mechanism pounds. . '< -19

Length of gun inches. . 90. 9

Caliber millimeters. . 75

Length of bore inches. . 84

Length, calibers 28

Rifling, right hand twist, zero turns from origin to point 2.89 inches from
origin; from this point increases one turn in 119 calibers to one turn in 25.4
calibers at a point 9.72 inches from muzzle. Uniform from this point to end
of muzzle.

Number of grooves

Muzzle velocity:

Shrapnel feet per second . . 1,

Shell (short fuze) .do 1,



Shell (long fuze) do. ... 1, 876


Maximum range:

Shrapnel (Mark IV shell) yards. . 9, 650

Shell (short fuze) '.do 12, 360

Shell (long fuze) , do. ... 11, 155

Weight of carriage, complete (without gun) pounds . . 2, 280

Weight of gun and carriage, fully equipped do 3. 045

Diameter of wheels inches. . 56

Width of track do 60

Length of recoil of gun on carriage (variable) do .... 18-46

Height of axis from ground do. ... 41. 625

Maximum angle of elevation degrees. . 53

Maximum angle of depression do 7

Maximum traverse, each side of center mils . . 400

Maximum angle of elevation with angle of site handwheel. . .. degrees. . 11

Maximum angle of depression with angle of site handwheel do. ... 7



The gun is of the built-up construction and consists of a tube,
jacket, locking hoop, breech hoop, and clip. There are six slightly
varying types of this gun, but the variations deal only with the
manner of attachment of the jacket and locking hoop and do not
affect the general dimensions. The gun is guided in recoil by two
flanges on the lower sido of the jacket. A lug on top near the for-
ward end of the jacket containing a T-slot, holds the forward end of
the recoil cylinder.

A short hoop or clip is shrunk on the tube near the muzzle and has
on its under side two lugs which form guides for the gun on the
cradle. Provision has been made to prevent dust from entering be-
tween the surfaces of the guides and their bearing surfaces on the

The breech ring, which screws to the rear end of the jacket, forms
a housing for the breech block which slides up and down with the
action of a wedge. The ring carries at the top a lug to which the
hydraulic recoil cylinder is secured, and at the bottom another to
which the two spring piston rods are attached.

The breech block is of the drop-block type and operates semi-
automatically, in that the breech closes automatically when a round
of ammunition is inserted, it is opened by pulling back a handle on
the right side of the breech, which not only slides the breech block
out of place but operates the extractor, thus ejecting the empty car-
tridge case. When a round is inserted smartly into the breech, its
rim strikes against the lips of the extractor causing the mechanism to
close under the action of the closing spring. The cartridge primer is
fired from the left side of the carriage by a continuous-pull firing
mechanism. The firing pin is cocked and fired by one continuous
backward motion of the firing handle.

The carriage is of the split-trail type which means that the trail is
made up of two halves, each being hinged to the axle near the wheels
and capable of being spread out at a wide angle or brought together
at the spade ends and locked for traveling. This feature permits
greater elevation and traverse than the ordinary type of trail and
reduces the necessity of shifting the trail when changes in deflection
of 50 mils or more are desired.

A seat is provided on each half of the trail, the one on the left for
the gunner who operates the sights, the traversing and angle of site
handwheels, and fires the piece, and the one on the right for a can-
noneer who sets off the range and angle of site and operates the
breech mechanism.





The recoil mechanism is of the hydro-spring variable recoil type
consisting of one hydraulic and two spring cylinders which comprise
the recoil and counterrecoil mechanisms. On account of the high
angles of elevation at which this gun can be fired, it was necessary
to design a variable recoil system by means of which the length of
recoil of the gun would be automatically lessened, the higher the
muzzle is elevated. This is accomplished by means of a valve turn-
ing in the cylinder and shutting off or opening a number of holes,
proportional to the elevation, thus making the resistance to the
passage of the oil greater or less.


The angle of sight mechanism consists principally of a rocker
which is moved by two hand wheels, one on each side of the gun.
Movement of the mechanism causes the gun, cradle, elevating mech-
anism, and sights to move also, they being connected to the rocker.
The handwheel on the left or gunner's side is used when laying for
direct fire, or in other words, when site is set independent of range.
The angle of sight scale is graduated in mils. All settings on the
angle of sight scale are set oft' above or below the 300-mil graduation,
this being the normal setting when the axis of the bore and the
target are in the same horizontal plane.

The elevating mechanism used in setting the range is mounted on
the rocker, and therefore independent of the angle of sight mechanism?
the gun and cradle only being moved upon operation of the hand-
wheel. The range scale is graduated in meters.

Band brakes are used on this carriage and are operated by a hand
lever in rear of the shield when in battery position and by a lever
from the axle seat when in traveling position.



The gunner and cannoneers are protected by the customary shields
and apron.

The sight used is of the model of 1916 type, which provides a sup-
port for the panoramic sight and the peep sight.

Wooden wheels, 56 inches in diameter, with steel hubs and tires, are
used, the tires being 3 inches in width. These wheels are interchange-
able with those of the caissons and limbers.

Fixed ammunition is used in the 75-millimeter field guns and is made
up of either common shrapnel or common steel shell. Shrapnel
rounds are issued with the projectiles filled and fuzed; the shell
rounds are issued filled but not fuzed and contain an adapter with
booster charge.

The projectiles average in weight: Shrapnel, 16 pounds, fuzed;
shell, 12.3 pounds, fuzed. The components of one round are the
cartridge case with primer, powder charge, projectile, and fuze in
shrapn.el, and adapter and booster in the shell. Weight of powder
charge is approximately 1.5 pounds.


A battery of 75-millimeter gun carriages, model of 1916, is accom-
panied by the following vehicles :

75-millimeter gun carriage limber, model of 1918.

75-millimeter gun caisson, model of 1918.

75-millimeter gun caisson limber, model of 1918.

Forge limber, model of 1902 Ml.

Store limber, model of 1902 Ml.

Battery and store wagon, model of 1917.

Battery reel, model of 1917. *

Reel, model of 1909 Ml.

Cart, model of 1918. 1

The above gun carriage was originally the 3-inch gun carriage,
model of 1913, which was later called the 3-inch gun carriage, model
of 1916. The gun was afterwards modified to caliber 75 millimeters,
as was the 3.3-inch British, thereby permitting interchangeability of
ammunition with the French guns.

1 For horse batteries the battery reel, model of 1917, is issued. For motorized batteries the reel, model
of 1909 Ml with the cart, model of 1918, is issued in lieu of the battery reel, model of 1917.

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Online LibraryUnited States. Army. Ordnance DeptHandbook of artillery : including mobile, anti-aircraft and trench matériel → online text (page 5 of 19)