The labor world., 1898-10-29
FLAWS IN BIG GUNS.

/ FLAWS IN BIG GUNS.
INTERNAL DAMAGE CAUSED BY sUC-
CESSlVE DISCHARGES
The "Erosive Action of Inhamed
! Gascs'' Causes the First Serious In
! jury-How the Projectile Helps to
Kill the Gun.
! The larger cannon the more exten-
sive are the injuries it receives with
each successive discharge. All damage
done to gun is internal. The separate
action of the powder and the projectile
damages the piece every time it is aimed
and fired. Obviously the amount Of the
damage depends upon the material and
workmanship Of the gun. Men who
make big guns describe the harm done
their pets with many intricate and puz-
zling terms Of scientific turn. In one
case gun is damaged because the part
of the bore which contains the powder
is enlarged. This happens when the
metal is compressed, and it is more dan
gerous and more plainly seen if the
gunners have been using wads between
their explosive and their projectile.
Then, again, cavities are produced by
the melting away of part Of the metal
by the heat of combustion Of the charge
Cracks come from the tearing asunder
of the PARTICLES of the metal at the sur
face Of the bore. When it is first made,
a crack Of this particular kind is barely
perceptible, but it increases each time
the gun is fired. Gradually it extends
completely through the side of the
piece. The crack usually begins at the
junction Of the chamber with the bore,
simply because, as guns now are, this
part is not SO we'll supported as the
others.
Edward S. Farrow, U. S. A., is au-
thority on damage to, guns, although,
like all others who have studied the
question, he does not agree with very
many authorities on all the points to
consider in the life of cannon. He con-
tends that furrowing or scoring produced
by the erosive action of indamed gases
is the great disease which attacks the
very big guns first. This particular in
Jury is most apparent where the current
of the gas is most rapid or at the inte-
rior orifice Of the vent and on the SUR
face of the bore, directly over the seat
Of the projecti]e. This scoring begins
very early in the life of very large
gun, but it is conceded that it does not
become very important until the piece
has been discharged considerably. Lieu
tenant Farrow describes this scoring as
RESENT bling the bark Of an aged elm tree,
the metal being eaten away into irregu-
lar burrows and ridges. In extreme
cases, however, scoring has not killed
the gun, although in some cases it has
acted like wedge and split the bore at
the place attacked.
Where the action Of the projectile has
ruined the gun the damage has been
done around the projectile and in front
of it. The elasticity Of the metal and
iAe orowding up Of portions Of it in
6rups Of the shot cause reboundinE
f< ocess. The projectile, carried forward
by the force Of the charge, strikes
against the upper part Of the bore; then
it is sent against the bottom and again
bounds to the top, and 60 on until it
emerges from the piece. The effect Of
this bounding motion is to raise and de-
press the gun in it's trunnion holes. The
accuracy Of fire is diminished, and, Of
course, the gun is unfit for service.
Bronze guns are the worst sufferers In
this way. Mortars-short and dumpy-
are not affected.
To stop the bounding Of the projectile
gunners wrap the shell in cloth or pa
per or else shift the base Of the mass
to be hurled. This last process is con-
bidered the best and is done by reduc-
ing the diameter Of the cartridge and
adding to it's length. Projectile injury
is also caused by furrows or scratches
made by rough shells or case shot.
Small fragments, too, break away very
often from the shells and give the bore
q grinding and cutting process, produc-
tive of great damage.
Enlargement of the muzzle is another
serious injury produced by the projec-
tile. This is caused by process which
seems unavoidable. AS the shell leaves
the piece it strikes against one portion
Of the bore. The resistance at the mouth
being less than at any other point, the
metal naturally yields, and the muzzle
Of the cannon: is elongated in vertical
direction.
Some men who ought to know say
that $50 shots is the life It very big
gun-a IL or 18 inch weapon. Others
place the number Of shots at 400 or 500.
AS a matter of fact, it is all guesswork.
The great Krupp gun shown at the
World g fair and conceded to be perfect