Improvements in Projectiles.
Year: 1893

page_text: Date of Application, 9th Mar., 1893
Complete Specification Left. 1st Nov. 1893-Accented. 2nd Dec. 1893
PROVISIONAL SPECIFICATION.
Improvements in Projectiles.
I, HUGH CECIL WALDEGRAVE HAMILTON Lieutenant, Queensland Artillery
of Victoria Barracks, Brisbane Queensland at present residing at 12, The Common,
Woolwich do hereby declare the nature of this invention to be as follows :-
I. In guns the sealing of windage and prevention of scoring by a ring of asbestos,
or other similar material, placed round the base of shell or other projectile, so that,
when loaded the ring will bear against front slope of chamber of gun.
The ring
to be either attached to projectile or put on after projectile is loaded. The ring may
be protected by a thin covering of copper or other material.
II. The impartance of rotation to the projectile by such a ring, suitably
attached, when fired from rifled guns.
1
1009
H. C. W. HAMILTON,
Lieut. Q. Art.
COMPLETE SPECIFICATION.
Improvements in Projectiles.
I, HUGH CECIL WALDEGRAVE HAMILTON, of Victoria Barracks Brisbane,
Queensland, Lieutenant Queensland Artillery, at present residing at Shoeburyness,
Essex, 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 :-
My invention relates to projectiles and is designed to prevent or diminish the
scoring, or erosion of the bore, which takes place when projectiles as at present
constructed are fired from guns.
Scoring or erosion of the bore is due to the passage of gas under pressure between
the projectile and the bore of the gun.
This scoring usually commences in guns on the upper part of the bore close to
the seat of the projectile and thence extends forward, becoming less marked as it
approaches the position of the trunnions and almost entirely disappearing in front
of that position.
Up to the present the means employed to prevent scoring or erosion of the bore
have not proved effective, chiefly for the following reason: When a projectile
provided with a driving band or gas-check as at present commonly constructed has
been rammed home in the gun only a small portion of the driving band or gas-
check is in contact with the bore of the gun; consequently on the charge in the
chamber of the gun being ignited but a small resistance is opposed to the escape
of the gases generated until the projectile has moved forward and the driving
band or gas-check been thereby forcibly driven into the grooves of the rifling and
against the bore of the gun.
Now the projectile cannot move forward until pressure sufficient to overcome
the inertia due to it's weight, and also to force the driving band into the grooves
of the rifling, has been developed. Consequently when the charge is ignited and
before pressure sufficient to move the projectile forward has been developed an
escape of gas occurs which scores or erodes the bore.
This escape of gas not only erodes the bore but also establishes grooves or
channels in the driving band, and, as these grooves or channels are not obliterated
until the projectile has been driven a considerable distance down the bore the gas

page_text: continues to escape and to damage the bore until, owing to the forward movement
of the projectile, the soft or ductile metal of the driving band is forced firmly into
the grooves of the rifling thus, either entirely or in a great measure, preventing
the further
escape of gas and consequent erosion of the bore.
Now the object of my invention is to provide a means of preventing or of
greatly diminishing the passage or rush of gas between the projectile and the bore
and thereby to prevent or diminish the scoring or erosion of the bore.
To accomplish this I use a packing ring capable of being readily driven
forward by a pressure of gas very much less than that required to move the
projectile.
This packing ring I make of asbestos or other light fibrous material or com-
bination of materials suitable for making a gas-tight joint between the projectile
and the bore. The asbestos or other material may be either woven, or twisted
into yarn, or otherwise prepared in any simple and convenient way commonly used
for the purpose of making gas-tight joints.
I arrange the packing ring on the projectile, in addition to the driving band
commonly used to impart rotation and prevent the escape of gas, in such a position
that when the projectile is rammed home in the gun and the said driving band is
gripped or held by the rifling of the gun, the packing ring shall be in contact
both with the driving band and with the bore, and will consequently, when
subjected to the pressure of gas acting in the chamber of the gun tend to fill up
any spaces or apertures between the front part of the driving band and the bore.
When thus using my packing ring in addition to a driving band I either simply
place the said packing ring round the projectile in front of the driving band and
make it a moderately close fit, such that when the projectile is rammed home the
front or bevelled part of the driving band will protrude through the packing ring
and be gripped by the bore in advance of it; or I fit the packing ring into a
suitably placed cannelure or circular groove on the driving band, or employ any
other simple and convenient means of attaching the packing ring to the driving
band and ensuring that when the projectile is rammed home the packing ring shall
be in the position above described relative to the driving band and the bore of
the gun.
.I sometimes alter the driving band at present commonly used by forming a
groove or cannelure round it, in rear of the packing ring, and of such shape and
dimensions as to contain the said packing ring, or a part of it, when the projectile
has been forced forward into the bore by the explosion of the powder charge.
And I may also cut small longitudinal channels or slots on the front or bevelled
part of the driving band for the purpose of allowing a small escape of gas and
ensuring the efficient action of the packing ring under a pressure insufficient to force
a passage between the said front, or bevelled part of the driving band and the bore
were such channels not provided.
The action of the packing ring when used as above described is as follows. On
the ignition of the powder charge in the chamber of the gun a certain quantity of
gas is evolved and this gas tends to find a way out of the chamber and in so doing
to pass between the front or bevelled part of the driving band and the bore of the
gun in the manner herein before described. Now the space immediately in rear of
the front or bevelled part of the driving band is occupied by the packing ring
which is consequently carried forward by the gas and pressed into every aperture
or opening between the front of the driving band and the bore, thus making a gas-
tight joint and preventing erosion. It is obvious that although the packing ring is
primarily used for the purpose of checking the escape of gas before a pressure
sufficiently great to move the projectile has been developed it's action is not limited
to that period but continues throughout the passage of the projectile down the
bore, for, when the projectile moves forward the packing ring is carried with it and
tightly compressed between the driving band and the bore.
I also, but chiefly in the case of light projectiles such as those used in the
smaller natures of ordnance, employ a packing ring of the nature herein described,

page_text: but of larger dimensions relatively to the projectile, for the purpose of imparting
rotation to the said projectile in addition to preventing the escape of gas.
For this purpose I use the packing ring with a projectile, part of which towards
the rear end, or base, is of less diameter than the main body, and having serrations
of a ratchet pattern on such part of less diameter, or being ribbed on such part, or
in any convenient way so shaped that when the packing ring is tightly compressed
between such part and the rifling of the gun no slipping of the packing ring relative
to the projectile shall take place.
I make the packing ring, when used as above described, of such thickness as just
to fit between the serrated or ribbed portion of the projectile and the bore when
tightly compressed, and I fix it to the projectile by means of a ring or rings of
copper or other suitable metal. I employ one such ring at the front of the packing
ring to assist in making a gas-tight joint by so placing it, that, when the projectile
is rammed home, the front of the said metal ring shall project in front of the
packing ring and be gripped by the bore in that position.
In the case of projectiles used in small-arms, and which are made of a combination
of lead and some harder metal which encases the lead, I provide for preventing the
escape of gas by making the rear part of such projectiles of less diameter than the
main body and I arrange on such rear part the packing ring already described, for
the purpose of preventing erosion.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is:
1. The herein described method of preventing the scoring or erosion of the bore
of a gun by the employment on the projectile of a packing ring of asbestos or other
suitable fibrous material capable of making a gas-tight joint between the projectile
and the bore of the gun when acted on by a pressure of gas less than that required
to move forward the projectile.
2. The combination in a projectile of the packing ring herein described with a
driving band of the nature at present commonly used, substantially as, and for the
purpose, set forth.
3. The combination in a projectile of the packing ring herein described with a
driving band provided with longitudinal channels or slots on the front or bevelled
part of the same, substantially as, and for the purposes, described.
4. The herein described method of imparting rotation to a projectile by means
of a packing ring of asbestos or other suitable fibrous material by the engagement
of the same, when tightly compressed, between the rifling of a gun and serrations or
ribs on the projectile, substantially as, and for the purpose, described.
5. A projectile for use in small-arms having it's rear part of less diameter than
the main body and having arranged on the said rear part a packing ring such as is
herein described for the purpose of preventing the escape of gas, substantially as,
and for the purpose, set forth'
Dated this 28th day of October 1893.
H. C. W. HAMILTON,
Lieut. Q'land Artillery,
Shoeburyness, Essex.