The Indianapolis journal. [volume] (Indianapolis [Ind.]) 1867-1904, 1898-05-29
MAKING OF MODERN GUNS
DIFFICULTIES TO BE OVERCOME IN
CASTING HEAVY ORDNANCE.
Machine, Rapid-Fire and Dynamite
Gums Are COmpIicated-The Big
Coast Defense Rifles.
Philadelphia telegraph.

body is more or less familiar, but ordnance
and machine guns, in the language of the
small boy stump most persons.
Ordnance includes high-power and rapid
| fire guns Guns of high power are those
which can throw a projectle at the rate of
| 1900 feet per second. These guns are gen.
orally of eight, ten, twelve or sixteen inches
| in caliber, and they do not fire fixed am
munition. Rapid-fire guns fire fixed ammu-
milton or ammunition in which the charge
and projectile form single piece. The
| size of these guns ranges from four inches
! in calber down. Both kinds of ordnance
| have these features in common, they are
breech-loading rifles, constructed in prac-
| tically the same way.
The progress in ordnance-making has
been achieved by aiming at four things
high power accuracy, rapidity of fire, and
resistance to the strains of discharge. This
! last is not the least important There are
! two strains on a gun as a result of the
sharp and tremendous expansion of the
| gas created by the combustion of powder.
| One of these strains tends to split the gun
| in the line of it's length and the other tends
| to pull the gun apart in places at right
| angles to its length. Now, as the effort TO
| attain higher power in the guns can only
be accomplished by using more powerful
explosives and heavier charges of them,
there is a consequent greater expansion OF
gas to be provided against
The strain which would pull the gun apart
does not offer so hard a problem. Modern
gunmakers consider that they have pro-
vided against it sufficiently in their precau-
items against the other strain. But this
other strain. the one which could split the
gun lengthwise, has prevented the greatest
difficulty. 1t is pretty successfully met.
however, by the modern buit-up gum This,
as it's name signifies. is not one homogene-
Gus piece, but is constructed out of a CEN
trail tube or jacket and number or hoops.
1t is built up" giving the gun stepped
appearance.
to the proper size, for the inner diameter
of the jacket, for instance is normally less
than the outer diameter of the tube, and
the inner diameter of the first hoop less
than the outer diameter of the Jacket, and
SO on. Then, beginning with the jacket,
these rings are shrunken over the tube by
cooling them rapidly with running water.
In this way starting from the outside, each
hoop or ring congresses the one next inside
of it, and is at the same time in a state OF
tension until the tube is reached.
This is a state of compression only and
the idea is that the state of compression
must first be overcome by the powder. gas
before the tube can go into a state of ex-
pansion The Jackets state of compression,
then, would have to be overcome before 1t
could go into a state of tension the reverse
of it's normal one, and so on, the strain on
the gun being divided up in this way among
all its parts.
THE GUN ASSEMBLED"
The steel of which the guns are made is
cast in solid ingots under hydraulic pres
sure and forged. The tubes are forged
solid the hoops and jackets are bored and
forged afterward. After the tube is bored
out nearly to finished size the other parts
are shrunk on or affixed; In other words,
the gun is assembled.
After assemblage the boring of the bore is
finished, and the rear end of it is bored out
to an increased diameter to form the pow
der chamber. A conical portion of the bore,
| called the compression slope, connects this
chamber with the main bore. Back of the
powder chamber is another contcal portion
called the gas check slope. This leads to the
screw box, which is threaded to receive and
hold the breech plug. When the bore is thus
finished and the outside of the gun has
had a finishing turning, and the trunnions
or arms for supporting the gun on its car
riage are fitted on, if the gun is to have
them, the next step is the rifling.
To do this the gun is securely fixed and
a ponderous round steel bar travels through
the bore from the breech forward, rotating
as it goes. This bar, called the rifing bar,
has a groove cut in it corresponding TO the
twist or inclination of the ritiing. required
and IN this groove stud works Whl en-
course the rif1ing winds spirally round the
bore, and as one looks through the gun
from the breech these rifle grooves will be
| seen to twist to the right. The number of
the grooves is regulated by the caliber OF
the gun in inches.
grooves each All the others of heavier cali
Der have as many grooves al four times the
caiber. The caliber of a rif1ed gun is the
diameter of a cylinder which touches the
highest points OF all the lands or the po-
sition of the bore between the grooves. But
If the lands are narrow and the grooves
wide the caliber is the diameter of a
| cylinder which touches the lowest points of
all the grooves.
After rifiing the gun is ready for fitting
on the breech mechanism. The great requi-
sites in this mechanism are that it should
automatically and completely stop the es-
cape of powder gas at the rear, that it
| should not weaken the gun, and that it
vices to-day which satisfy these require
ments effectually are almost numberless in
their variety.
The, chief part of the breech device is
| the screw gas check, and the chief part of
| the check is the breech block or plug, which
| screws into the screw box at the end of the
| bore. 1t is to be remembered that this
| screw box IS cut in the jacket and not in
the tube. The other mechanisms contain
divers sorts of pads, nuts and washers to
help resist the gas and to make the work.
! The gas check generally has a mushroom
| head which projects into the tube, and
| through the shank of this mushroom head,
| which runs through the center of the breech
block, the vent is bored. The opening of
I
breech block till it swings clear of the
screw box on trap prepared to receive it,
! The gun is now finished except for the
| tests or proofs made by firing it certain
number OF times with different charges. If
it is proved satisfactorily. 1T is ready for
mounting. OF course the mount depends
on the use to which the gun is to be put
1t is first necessary that there shall be a
mount in order that the gun may be trained
or sighted and held so that there shall be
no deviation from the line of flight planned
for the projectile
DISAPPEARING MOUNTS.
After this the mount must be constructed
with view to overcoming the recoil. In
ventions to take up the recoil have been
many and successful, ranging from the re-
sistance offered by @ piston working in a
cylinder to slides by which the force of
gravity, acting on the weight of the gun,
brings the gun back into position after re-
coil. There are also nonrecoi mounts
fitted to guns of small caliber. Field guns.
of course, take up recoil with great free
dom. The recoil devices are only needed
for fixed mounts in Notifications and on
board vessels.
Great mystery surrounds the disappear
ing mounts for guns in Notifications. They
raise the gun for firing and lower 1t for
loading, and as the gun can be sighted by
range-finders the gunners are not exposed.
disappearing mounts was made the other
day by officer of high rank. He said:
I'VE have the best gun mounts, especially
of the disappearing kind, here in America
l Travelled two years in Europe inspecting
ordnance and learning all that / could
81 4oI sw1xvn to-