IMPROVEMENTS IN ORDNANCE AND FIRE-ARMS, AND IN TOOLS FOR RIFLING THE SAME
Year: 1860

page_text: PROVISIONAL SPECIFICATION left by Perceval Moses Parsons at the
.Office of the Commissioners of Patents, with his Petition, on the 13th
July 1860.
I, PERCEVAL MOSES PARSONS, of Arthur Street West, London Bridge,.
in the County of Middlesex, Civil Engineer, do hereby declaro the nature
of the said Invention for "IMPROVEMENTS IN ORDNANCE AND FIRE-ARMS, AND IN
TOOLS FOR RIFLING THE SAME," to be as follows:-
In constructing cannon according to my Invention, I form an outer shell
or casing of cast iron, which I bore out cylindrical or slightly conical, and
force into it a tube of wrought iron, steel, homogeneous metal, or other suitable
metal or alloy turned to fit the interior of the cast-iron casing. In some
cases, for heavy guns, I employ besides the inner tube an additional tube of
any suitable metal or alloy bored to receive the inner tube, and turned to fit
the interior of the shell or casing; this I force into the outer shell or casing,.
and the inner tube I force into it. For very large guns, two or more tubes,
fitting the one into the other, may be employed in like manner.
In guns intended to load at the breech, I bore them right through, and
form an annular recess around the bore in the interior of the breech near the
end, and I close the breech end by means of a plug provided with suitable
lugs which take into the annular recess. To enable the plug to enter, and its
Jugs to pass into the annular recess, channels or passages are made in the
flange enclosing the same to allow the lugs to pass, and the plugs being intro-
duced, it is turned partly round so as to bring the lugs in such a position that

page_text: they will be covered by the remaining portions of the external flange enclosing
the annular recess, by which means the plug is held in its place, and pre-
vented from being forced back when the piece is discharged. The plug may
be entirely loose, and introduced and removed by hand, but in some cases, and
particularly in heavy guns, I suspend it by an arm or frame in which it can
turn freely to a hinge or rod attached to the gun in such a manner that it can
be moved in and out of its place, and be turned on one side so as to allow the
charge to be introduced. For the purpose of preventing leakage at the plug,
I employ a ring or flange of copper or other suitable metal or alloy provided
lip which embraces the plug, and which the pressure of gas at the
discharge of the piece tends to collapse around it, and thereby make tight
the joint.
In rifling the barrels of ordnance and fire-arms, I make use of a cutting
tool of steel turned or otherwise made to a cylindrical form, and having
angular teeth, grooves, or serrations turned or cut in it which form the cutting
edges, and for the finishing tool I employ a cylinder of steel highly polished
without cutting edges; these are placed in a suitable mandrill, and drawn
through the barrel undergoing the process of rifling in the usual manner; by
varying the diameter and length of the cylinders, in relation to the diameter
of the bore and rate of twist of the rifling, a great variety in the form of the
grooves may be produced at pleasure, and a more correct form and more-
highly polished surface obtained than when the cutters are filed into shape by
hand.