Reporter and farmer. [volume] (Webster, Day County, Dakota [S.D.]) 188?-1946, 1899-08-24
FLAWS IN BIG GUNS.
INTERNAL DAMAGE CAUSED BY Suc-
cESSlvE DISCHARGES.

OAseS" causes the FfrSt serious IN
jury-How the Pr~ojectile Helps to
XII the Gun.
Tho larger a cannon the more extern
sive are the injuries it receives with
each successive discharge. All damage
done to a gun is internal. The separate
action of the powder and the p~rojectile
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.
cling terms of a scientific turn. In one
cas- a gun is damaged because the part
Of the bore which contains the powder
10 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 a 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 SIR
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 well supported as the
pthers.
Edward S. Farrow, U. 5. 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 q cannon. He con-
tends that furrowing or scoring produced
by the erosiye action Of infiamed 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 oven the seat
of the projectile. This scoring begins
very early in the life of a 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
resembling the bark of an aged elm tree.
the metal being eaten away into irregn-
lar burrows and ridges. In extreme
cases. however. scoring has not killed
the gun. although in some cases ii has
acted like a wedge and split the bore at
the place attacked.
Where the action of the projectile has
ruined the gun the damage las been
done around the projectile and in front
of it. The elasticity of the metal and
the crowding up of portions of il in
front of the shot cause a rebonnding
process. The projectile. carried forward
by the force of the charge, strikes
against the upper part Of the bore; then
il Is sent against the bottom and again
bounds TO the top, and SO on until il
enaerges from the piece. The effect of
this bounding motion is to raise and de-
press the gun in its trunnion holes. The
accuracy Va fire is G...nished, aud, Of
course. the gun is unfit for service
Dronze guns are the worst sufferers IL
this way. Mortars-short and dumpy-
are not affected.
To stop the bounding cf the ~projectile
gnnners wrap tho she'll in cloth or pa.
per or else shift the Ease Of the mass
to be hurled. This last process is con-
sidered the best and is done by reduc-
ing the diameter of the cartridge and
adding to its length. Projectiie injury
Is also caused by burrows or scratches
made by rough shells or case shot.
Small fragments, too, break away very
often from the shells and give the bore
a 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 o 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 a vertical
direction.
Some men who ought to know say
that 100 shots is the life Of a very big
gun-a IL or Ii inch weapon. Others
place the number of shots at 400 or 500
As q matter Of fact it is all guesswork
The greas Knapp gun shown at tie
Worlds fair and cosesaed 10 be perfect
-or supposed TO be so-has been dis
charged less than ten times, and is is
now believed 70 have reached its limit
On the other hand, the big guns of the
American batueships have passed the
time allotted them by wise men who
know guns and apparently are as good
40 when tested How o they MAJ
yield. however. is not in the books
Lieutenant Farrow says that = very
large gun should not be expected @
stand more than 400 or 500 shots befcre
il will be necessary to open q new vent
closing the old one at its interior ri6ce.
When ghe gun dies-barsts-Ske lines
Of fracture are photographed Speci-
mems of the metal are saved Tegts are
made and conclusions drawn. Anu I'm
Gle Sam has figured ont so many things
in this same connection that his guns
powadavS are ennrp3e1 m ha ho.rnr rhan