IMPROVEMENTS IN CENTRAL- FIRE CARTRIDGES POR BREECH-LOADING FIRE-ARMS
Year: 1868

page_text: LETTERS PATENT to John Abraham, of Birmingham, in the County of
Warwick, Machinist, and Thomas Richard Bayliss, of Birmingham,
aforesaid, Machinist, for the Invention of "IMPROVEMENTS IN CENTRAL-
FIRE CARTRIDGES POR BREECH-LOADING FIRE-ARMS."
Sealed the 12th June 1868, and dated the 20th March 1868.
PROVISIONAL SPECIFICATION left by the said John Abraham and
Thomas Richard Bayliss at the Office of the Commissioners of
Patents, with their Petition, on the 20th March 1868.
We, JOHN ABRAHAM, of Birmingham, in the County of Warwick,
Machinist, and THOMAS RICHARD BAYLISS, of Birmingham, aforesaid,
Machinist, do hereby declare the nature of the said Invention for "Im-
PROVEMENTS IN CENTRAL-FIRE CARTRIDGES FOR BREECH-LOADING FIRE-ARMS,"
to be as follows:-
In constructing the said cartridges according to our Invention we
form the cases or shells by preference of sheet metal; they may,
however, be formed partly of metal and partly of paper or other flexible
non-metallic material.

page_text: In making the said cases or shells of metal we draw them solid
from a disk or cut them in proper lengths from tubes. We make
a series of incisions or depressions in the metal cases or shells, the
said incisions or depressions being either parallel to the axis of the
case or shell or oblique thereto or situated in a helical direction. The
said incisions or depressions permit the case or shell to expand on
firing, thereby preventing the escape of gas. After discharge the
case or shell contracts and the empty case is readily extrated from
the fire-arm. A thin metallic or other lining is used to more effectually
prevent the escape of gas. An inner or percussion chamber for holding
the percussion pin herein-after described is situated at the base of
the cartridge, and in its axis. It consists of a cup formed in the middle
of a blank or disk of metal, which disk is fixed in the rim of the case
or shell, being held firmly between the two sides of the said rim. The
bottom of the percussion chamber is convex internally, and constitutes
an anvil for the percussion pin to strike against; a separate anvil is
thereby rendered unnecessary. The said convex bottom of the per-
cussion chamber is pierced with a small hole for the fire or flash to
pass through to the gunpowder of the cartridge. The base of the case
or shell is pierced with a hole the edge of which is turned inwards
upon the percussion chamber, which turning inwards of the edge tends
to prevent the escape of gas. The percussion pin is a solid piece of
metal or wire of a size proper to fit the percussion chamber, that is,
about the size of a percussion cap. The inner end of the percussion
pin is made concave, and in the concavity the charge of fulminate is
put. The primed percussion pin is inserted through the hole in the
base of the cartridge into the percussion chamber in the said base,
which chamber it fits accurately, the fulminate coming nearly in contact
with the anvil or convex bottom of the percussion chamber. When
the percussion pin is struck by the hammer or striker of the fire-arm
its primed end strikes against the convex bottom or anvil of the
percussion chamber and ignites the cartridge. We employ a wad in
the base of the cartridge, which wad is of the ordinary kind, and is
inserted in the cartridge in the usual manner.