IMPROVEMENTS IN ORDNANCE, APPLICABLE ALSO TO SMALL ARMB
Year: 1861

page_text: PROVISIONAL SPECIFICATION left by John William Gibson at the Office
of the Commissioners of Patents, with his Petition, on the 30th November
1861.
I, JOHN WILLIAM GIBSON, of the Firm of Messrs. Turner and Gibson, of
the Hammersmith Iron Works; Dublin, do hereby declare the nature of-the
said, Invention for "IMPROVEMENTS IN ORDNANCE, APPLICABLE ALSO TO SMALL
ARMB," to be as follows:-
This. Invention relates to that class of ordnance or arms, in which, the
projectile employed is intended to be inserted or charged in at the breech.
It,consists in substituting for any of the ordinary means beretofore employed
for closing the breech end of the bore a vent piece or flat plug slightly tapered
to ensure proper fitting and allow for wear, which vent piece or plug is made
to fit into a suitable slot or opening, having parallel sides or grooves for its
reception and guidance. Instead of employing a vent piece or plug of the
form and description used in the guns of Sir William Armstrong, which has
to be lifted out from the top and replaced by hand, I form my vent. piece.or
plug in the following manner :-I make it of such a length that whilst the
solid part or portion shall oppose sufficient surface and solid resistance to the
explosive force of the powder when the breech is closed, there is, near, to
the one end thereof, a clear opening or hole bored therein for. the purpose of
permitting the charge to be inserted when the vent piece or plug shall have
been raised, depressed, or moved aside, to the right or left, as the case may be,
so that the axial line of the bore of the arm shall coincide with the opening or

page_text: holc in the vent piece or plug. I prefer to form the vent piece or plug
parallel in width, and with side wings or guide pieces formed parallel in their
thickness, so as to work in a parallel groove or recess formed on each side of
the opening in the breech formed to receive the vent piece or plug. Now,
instead of lifting or removing and replacing the vent piece or plug by hand,
as in the Armstrong gun, I apply a screw, which is connected thereto, and
which may either have a revolving nut with a "fly" or lever arm for giving it
motion, or projecting it inward and outward to the, required extent, or the
point of the screw may revolve in a suitable recess formed in the one end of
the vent piece or plug, and having a lever arm or "fly" secured to the other
end of such screw, it is free to work backward and forward in a fixed nut,
and so project or withdraw the vent piece or plug. Now, to enable the
increased length of the vent piece or plug, which is necessitated by the nature
and construction thereof, to be protected and confined within the breech of the
gun, or the solid part thereof, and for the purpose of protecting it, as well as
enabling the necessary attachments to be made for the purpose of giving
motion to the vent piece or plug, I have forged on to and as a part of the
breech on the under side thereof, or to the right or left thereof, as may be
preferred, a projection of such a sise and form as may best suit the purposes
for which I have stated its being requisite. And although I prefer to forge
this projection solid, or as a portion of the breech of the arm, yet it may be a
separate forging and bored and shrunk on, or otherwise fitted or attached
thereto. Although the moveable vent piece or plug may be parallel in its
width, and be made to slide in parallel grooves of a suitable width and depth,
yet I prefer that in thickness or depth such vent piece or plug should not be
parallel but slightly taper or wedge-like, and such taper or inclination to the
axial line of the bore may either be on its front face, or on the back thereof,
so that when the charge has been passed through the opening in the plug into
its proper position in the chamber or bore, the breech is then closed by the
solid part of the vent piece or plug, the slightly increased depth thereof is
made to fill the opening and effectually prevent the escape of gas, and at the
same time expose a solid resistance to the explosive force of the powder.
Instead of forming the vent or means of communicating ignition to the
charge within the bore by drilling a hole in the breech in advance of the sliding
vent piece or moveable plug, I prefer to form such passageway or means of
communicating ignition to the charge by drilling a hole in the moveable plug
and by suitably forming its upper or exterior end; the ordinary appliances or
means of discharging the arm may be attached or applied thereto.
As a means of readily regulating or adjusting the exact position of the

page_text: sliding vent piece or plug to ensure the coincidence of the opening therein with
the bore of the arm, a pin or sliding bolt may be applied to the side edge or
back of the sliding vent piece or plug, so that its point may enter a hole or
notch drilled in the proper place, and such sliding bolt or pin may be of
sufficient length to project from the solid part of the arm, and may have a
spiral spring or other means of keeping it out of action until required.
In applying the present Invention to breech-loading small arms, such
changes in the shape and proportions of the parts may be made as to enable
the said Invention to be applied thereto, and subject only to such changes of
form and proportion. I have herein described generally the mode in which
I should adapt my said Invention to small arms.
The mechanism for producing the sliding motion of the vent.piece or plug-
may be applied below or at either side of the breech, or in any other part of
the circumference of the breech, as may be preferred.