Improvements in Gas-operated Guns.
Year: 1898

page_text: PROVISIONAL SPECIFICATION.
Improvements in Gas-operated Guns.
We, THE HOTCHKISS ORDNANCE CO., of 49, Parliament Street, S.W., in the
County of London (a communication from abroad by Laurence Vincent Benét,
Artillery Engineer, of 21, Rue Royale, Paris, France), do hereby declare the
nature of this invention to be as follows;-
These improvements relate to that class of guns in which a portion of the pow-
der-gas is utilized for operating the breech mechanism of the fire-arm and more
particularly to that class of automatic machine-gun described in our Letters-
Patent of Great Britain dated March 10 1896, No. 5426.
The object of this invention is to provide means whereby the gun will operate
automatically when firing "blank" ammunition, that is, ammunition wherein
the metallic bullet has been replaced by a wad, wooden or paper
bullet, or other relatively light projectile. This class of guns is operated
by allowing a portion of the powder-gas to escape through a port or
channel drilled in the barrel, and to impinge against one of the moving parts of
the mechanism. When using ordinary ball" ammunition, the gas escapes under
pressure sufficient to operate the mechanism, but with blank ammunition, the
pressure is not nearly sufficient to produce the desired result.
Our invention consists, broadly speaking, in applying a pierced plug to the
muzzle of the gun for reducing the area of exit of the frangible blank bullet or
wad and gas, and thereby forcing a sufficient quantity of gas to pass through
the port or channel and operate the mechanism.
In the accompanying drawing, which illustrates the invention, Fig. 1 is a
vertical longitudinal section of the muzzle end of the barrel, showing the device
applied thereto.
Fig. 2 is a cross-section of the device, the plug being shown in end view, not
in section.
Fig. 3 is a front elevation of the device.
At the muzzle end of the barrel a is formed the annular projection b, which is
finished to the rear by a conical surface c, and the muzzle is counter-bored to form
a conical bearing d; this form of muzzle has no effect upon the ballistical qualities
of the gun.
The essential portion of the device is a plug e, which is coned to the rear to
register with the counter-bore d, and in which is formed a channel g of experi-.
mentally determined area, so as to cause the required amount of gas to pass

page_text: through the port or channel (not shown) formed in the barrel, and to impinge
against the moving or motor element of the mechanism of a gas-operated gun.
The channel g is bell-mounted at f in order that the fragments of the blank bullet
or wad may be guided into the channel g.
The
The plug e is mounted in a casing hand is held therein by a pin i which passes
through the casing and engages in an annular groove j cut on the plug.
groovej, being wider than the diameter of the pin, the plug has a slight longi-
tudinal play in the casing. Between the casing and the plug e is interposed a
"Belleville" or other suitable spring and, on the cylindrical surface of the
plug, are cut longitudinal grooves 7; a series of lateral vents m are drilled through
the casing in line with the groove j.
The object of this combination of spring k, grooves 7 and vents m, is to provide
means whereby, in the event of excessive pressure, the spring would permit the
plug e to move slightly to the front and the surplus gas to pass between the sur-
faces in contact at d, and thence through the grooves and vents m to the open
air.
To the rear, the casing his formed into a number of flexible arms n, n which
may be readily sprung over the annular projection 6 of the muzzle and engaged
with the conical surface c.. In order to facilitate springing these arms into place,
they are coned to the rear at o. In order to prevent the arms springing out of
place when firing, we provide a lock p, which engages with the screw-thread g
on the exterior of the casing h. The lock is provided with a conical bearing
surface r, which, on screwing the lock home, will bear on corresponding sur-
faces on the arms n, forcing and holding them in engagement with the conical
surface c. To facilitate screwing up and unscrewing the lock p, we form upon
it a handle s. To prevent the lock 2 from unscrewing, we provide a pawl t,
which is mounted on a pivot u in the lock, and actuated by a spring v.
The toe
of the pawl engages between the arms n, n of the casing h. In the casing is
formed a central hole in a line with the channel g.
t
The device is mounted on the gun as follows: The lock ? being unscrewed,
and the arms n, n freed, the device is centered on the muzzle and pushed into
place. The casingh being held with a spanner by means of the squared pro-
jection w, the lock is screwed home by means of the handle s. When fully home,
the pawl t engaging between two of the arms n, n prevents any unlocking during
firing. The diameter of the lock p is such as to mask the fore-sight of the gun,
in order that the gunner may be warned not to fire with "ball" ammunition.
Whilst the device is shown in combination with a complete and convenient
mechanical arrangement for attaching it to the muzzle of the gun, it is evident
that the area-reducing plug e, which is the essential part of the device, may be
attached by many other very obvious mechanical means, such as simply screwing
to the muzzle, engaging with a bayonet joint or otherwise.
Dated this 7th day of May 1898.

page_text: Artillery Engineer, of 21, Rue Royale, Paris, France), do hereby declare the
nature of this invention and in what manner the same is to be performed, to be
particularly described and ascertained in and by the following statement:-
These improvements relate to that class of guns in which a portion of the pow-
der-gas is utilized for operating the breech mechanism of the fire-arm and more
particularly to that class of automatic machine gun described in our Letters
Patent of Great Britain dated March 10, 1896 No. 5426.
The object of this invention is to provide means whereby the gun will operate
automatically when firing "blank" ammunition, that is, ammunition wherein
the metallic bullet has been replaced by a wad, wooden or paper.
bullet, or other relatively light projectile. This class of guns is operated
by allowing a portion of the powder-gas to escape through a port or
channel drilled in the barrel, and to impinge against one of the moving parts of
the mechanism. When using ordinary "ball" ammunition, the gas escapes under
pressure sufficient to operate the mechanism, but with blank ammunition, the
pressure is not nearly sufficient to produce the desired result.
Our invention consists, broadly speaking, in applying a pierced plug to the
muzzle of the gun for reducing the area of exit of the frangible blank bullet or
wad and gas, and thereby forcing a sufficient quantity of gas to pass through
the port or channel and operate the mechanism.
In the drawing, filed with our Provisional Specification, which illustrates the
invention, Fig. 1 is a vertical longitudinal section of the muzzle end of the barrel,
showing the device applied thereto.
Fig. 2 is a cross-section of the device, the plug being shown in end view, not:
in section.
Fig. 3 is a front clevation of the device.
At the muzzle end of the barrel a is formed the annular projection 6, which is'
finished to the rear by a conical surface c, and the muzzle is counter-bored to form
a conical bearing d; this form of muzzle has no effect upon the ballistical qualities
of the gun.
.
The essential portion of the device is a plug e, which is coned to the rear to
register with the counter-bore d, and in which is formed a channel g of experi-,
mentally determined area, so as to cause the required amount of gas to pass:
through the port or channel (not shown) formed in the barrel, and to impinge
against the moving or motor element of the mechanism of a gas-operated gun.
The channel g is bell-mouthed at f in order that the fragments of the blank bullet
or wad may be guided into the channel g.
The plug e is mounted in a casing hand is held therein by a pin i which passes
through the casing and engages in an annular groovej cut on the plug. The
groove j, being wider than the diameter of the pin, the plug has a slight longi-
tudinal play in the casing. Between the casingh and the plug e is interposed a
"Belleville" or other suitable spring and, on the cylindrical surface of the
plug, are cut longitudinal grooves ; a series of lateral vents m are drilled through
the casing in line with the groove j.
The object of this combination of spring k, grooves and vents m, is to provide
means whereby, in the event of excessive pressure, the spring would permit the
plug e to move slightly to the front and the surplus gas to pass between the sur-
faces in contact at d, and thence through the grooves and vents m to the open
air,
To the rear, the casing his formed into a number of flexible arms n, n which
may be readily sprung over the annular projection b of the muzzle and engaged
with the conical surface c. In order to facilitate springing these arms into place,
they are coned to the rear at o. In order to prevent the arms springing out of
place when firing, we provide a lock p, which engages with the screw-thread q
on the exterior of the casing h. The lock is provided with a conical bearing.
surface r, which, on screwing the lock home, will bear on corresponding, sur-

page_text: faces on the arms n, forcing and holding them in engagement with the conical
surface c.
To facilitate screwing up and unserewing the lock 7, we form upon
it a handle s. To prevent the lock from unscrewing, we provide a pawl t,
which is mounted on a pivot u in the lock, and actuated by a spring . The toe
of the pawl t engages between the arms n, # of the casing h. In the casing is
formed a central hole in a line with the channel g.
The device is mounted on the gun as follows: The lock ? being unscrewed,
and the arms n, n freed, the device is centered on the muzzle and pushed into
place. The casingh being held with a spanner by means of the squared pro-
jection w, the lock is screwed home by means of the handle s. When fully home,
the pawl engaging between two of the arms n, n prevents any unlocking during
firing. The diameter of the lock p is such as to mask the foresight of the gun,
in order that the gunner may be warned not to fire with "ball" ammunition.
Whilst the device is shown in combination with a complete and convenient
mechanical arrangement for attaching it to the muzzle of the gun, it is evident
that the area-reducing plug e, which is the essential part of the device, may be
attached by many other very obvious mechanical means, such as simply screwing
to the muzzle, engaging with a bayonet joint or otherwise.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed, we are aware that before
the date of our application it has been proposed, with guns firing blank cartridges,
to attach near the muzzle of the gun a tubular extension, provided with a conical
passage the diameter of which at its forward end is considerably smaller than
the bore of the gun, such conical passage being enlarged at its rearward end to
form a chamber into which the powder gases expand and then act upon the front
end of the barrel thereby driving the barrel backwards to operate the breech
mechanism, and we do not claim such construction, but we declare that what we
claim is:-
1. In a gas-operated gun, the means of increasing the gas pressure in the
barrel, consisting in reducing the calibre at the muzzle, whereby the pressure of
the powder-gases may be utilized to operate the gun, substantially as described and
shewn and for the purpose set forth.
2. In a gas-operated gun, the combination, with the barrel, of a muzzle-plug
having an axial channel of smaller calibre than the bore of the gun, whereby the
pressure of the powder-gases may be utilized to operate the gun, substantially
as described and shown, and for the purpose set forth.
3. In a gas-operated gun, the combination, with the barrel, of a muzzle-plug
having an axial channel of smaller calibre than the bore of the gun, and held in
elastic contact with the muzzle, substantially as described and shown, and for the
purpose set forth.
4. In a gas-operated gun, the combination, with the barrel, of a muzzle-plug,
substantially as described, means for holding it in elastic contact with the muzzle
of the barrel, and means for allowing any surplus gas to escape in the open air,
substantially as described and shown.
5. In a gas-operated gun, the combination, with the barrel, of a muzzle-plug,
substantially as described, a casing for the muzzle-plug, means for holding the
latter in the casing, means for holding the muzzle-plug in elastic contact with
the muzzle of the barrel, and means for allowing any surplus gas to escape in the
open air, substantially as described and shown.
6. In a gas-operated gun, the combination, with the barrel, of a muzzle-plug,
substantially as described, a casing for the muzzle-plug, means for holding the
latter in the casing, means for holding the casing to the muzzle, means for holding
the muzzle-plug in elastic contact with the muzzle of the barrel, substantially
as described and shown, and for the purpose set forth.
7. In a gas-operated gun, the combination, with the barrel, of a muzzle-plug,
substantially as described, a casing for the muzzle-plug, means for holding the

page_text: latter in the casing, means for holding the casing to the muzzle, means for holding
the muzzle-plug in elastic contact with the muzzle of the gun, and means for
preventing unlocking during firing, substantially as described and shown, and for
the purpose set forth.
W. LLOYD WISE,
46, Lincoln's Inn Fields, London, W.C.,
Chartered Patent Agent.