The weekly pioneer and Democrat. [volume] (Saint Paul, Minn. Territory) 1855-1865, 1862-11-28
Something About Gums and Pr0jec.
tiles. .

The science of gunnery, which so Ing
has been study with military men, has,
since the advent of the civil war ii Amer
lea, been the subject of deep Investigation,
and the state of public affairs has brought
to light may valuable improvements in
guns and projectiles
In the manufacture of heavy cannon
there has been much Improvement. In
1920, the 24-pound American gun was the
maximum size in use. In 1850 our largest
guns were lO-inch bore, and in 1862, (the
present Year,, weare manufacturing heavy
seige and naval guns of from Is to 20
inches bore heavy guns of immense size
and powe. To Captain John A. Dahl
gren, Of the United States Navy, and the
late General Rodman, of the Ordnance
Department, the country is much indebted
for improvement in heavy guns, especially
in rifed ordnance.
THE DAHLGREN GUN.
Captain John A. Dahlgren, a naval Off
Ger OF Swedish extraction, and now Ord
nance Officer in chief of the United States
Navy, has been for over twenty years ex-
perimenting in guns and projectiles, and
has attained worldwide reputation among
the most scientific officers on the globe.
His shell guns for naval purposes cannot
be excelled. These shell guns of 8 and II
inch caliber are now very generally used.
The chief improvement which Capt Dahl
gren claims, is in the reduction of the pro-
portion of metal between the muzzle and
the trunnions, which is found in guns of
the common mould to be largely in excess.
The weight is thus placed about the breech,
where the strength is needed. The size of
the Dahlgren guns, the S-inch shell and
the 32-pounder gun, which are the most
used for ordinary pu poses, may be found
in the following table
THE DAHLGREN INCH SHE'LL GUN
i.cnStn ol pore. ............ IOOo inches
Weight NEUTRALITY-SUSPICIOUS.. 63 cwt
Range of5e elevation, 8 feet above
water line, charge 8 lbs ....1. 77G yards
DAHLGREN 24-poUNDER.
Length OF bore ............... 1915 inches
weight % cWt
Range of 50 elevation, 8 feet above
water line, charge 8 lbs. ...... $40 yards
Captain Dahlgren is now making a
large number of Is inch guns, and has
had orders from the Government to make
some of the immense calibre OF 20-inch.
Besides these shell and II inch guns, he
is constructing large number of brass
boat howitzers, which for ship crews are
very effective. But to ritied ordnance is
he more particularly turning his attention,
having, at the Washington Navy-yard, a
large number OF the new brass rified guns
for firing the Sawyer projectile. He has
improved upon his gun by adding heavy
wrought brass band around the breech,
thus greatly increasing the strength of the
gun, and rendering it less likely to burst
when overcharged. He has within the
past two years, instituted q practice bat
terry at the Maynard in Washington, at
which, daily, every new gun which comes
in from the foundry is thoroughly tested
and inspected before being used. A prof.
cheney is attained in the manufacture of
this rified ordnance by Captain Dahlgren
which cannot be excelled in this or any
other country.
THE RODMAN GUN.
This gun was invented by Captain j.
F. Rodman, of the United States Ord
nance Department. 1t is piece ofheavy
ordnance, cast hollow, by the following
method: A core is formed on tube of
cast iron, which tube is water tight, and
close at the bottom, and is placed in the
axis of the mould Into the bottom of
this tube, through a smaller one, placed in
the centre, current of water is discharged,
after the casting, and ascending above the
top of the piece, constantly passes off,
cooling the interior When the cannon is
taken out of the mould, it is placed in a
lathe, being secured at one end by the
square block cast on the end of the casca-
bel, and the other placed in collar, lit
tie back of the muzzle, in which it can
revolve. The first operation is to cut off
the head, which is two to three feet long.
The object of this addition to the gun is,
that the upper part of the casting, usually
the weakest, may be rejected. The piece,
if solid, is then bored, steel cutter, fixed
at the end of the bar, being made to pene-
trate as the gun slowly revolves in its
frame. When the boring is completed,
the gun is finished on the outside by the
tools used in turning iron. 1t is then taken
out of the frame, the square block is cut
out of the casecabel with a cold chisel,
and the trunnions are dressed with the
same instrument. The touch-hole, is drill
ed with stock and list, and the gun is
ready to be proved, which is done by test
ing cylinder of the iron an inch in diam
eter and two inches long, cut out of the
cannon. This was formerly taken from
the trunnions, but now from the band near
the muzzle The specific gravity and other
properties of the sample are carefully noted,
and then, together with the trials to which
it is subjected, and the hardness of the
metal determined by very exact method,
gives current indications of the strength
Of the gun, without the necessity of submit
ting it to extreme proof by firing, with con-
stantly increasing charges, until the piece
is destroyed.
FIELD GUNS.
Among the light batteries used in the
service may be found the ordinary rifled
6-pounder gun, of Cabotrille manufacture,
the Napoleon 12-pounder brass howitzer,
and the Parrot gun, the latter of which is
an iron field piece of great utility, and ex-
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