IMPROVEMENTS IN PROJECTILES
Year: 1862

page_text: PROVISIONAL SPECIFICATION left by John Ward Girdlestone at the
Office of the Commissioners of Patents, with his Petition, on the 14th
May 1862.
I, JOHN WARD GIRDLESTONE, of the Canada Works, Birkenhead, in the
County of Chester, Civil Engineer, do hereby declare the nature of the said
Invention for "IMPROVEMENTS IN PROJECTILES," to be as follows:-
In one part of my Invention, which has been already partly explained
in the Provisional Specification of Letters Patent granted to me on the 23rd
January 1862, N° 187, for an Invention of "Improvements in Projectiles
for Fire-arms," I encase the shot or projectile for rifled ordnance or fire-arms
in a jacket of wood, papier maché, or other suitable material, so that the
jacket fits the bore, and being urged against the wedge-shaped rear of the.
ball, which is at first not quite home in the jacket by the explosion is
expanded into the grooves of the bore. The jacket receives a rotary'
motion from the grooves and imparts the motion to the projectile by means
of a projection in the jacket and recess in the projectile, or vice versa. The
jacket falls off or comes to pieces after it has left the gun, this operation
being sometimes facilitated by longitudinal saw cuts extending from the front
towards the rear. The jacket may have annular or cellular recesses so as to
reduce the friction and diminish the weight, and to strengthen the rear a
plate of metal or other resisting material, and where shot for rifled or smooth
bore ordnance is to be used against armour plates the head or striking part

page_text: of the projectile may be made slightly concave to improve its penetrating
powers.
In another part of my Invention, in some cases where it is to be used for rifled
ordnance I use a jacket made according to my Invention, as above or here-
after described, and of such a form and size as will cause it through the whole
or part of its length to fit the bore and the grooves of the ordnance before it
is put in with only the requisite windage. For smooth-bore ordnance or fire-
arms I sometimes use a jacket to hold a ball, winged or grooved, and rotating
by the action of the atmosphere during its flight, for which purpose the jacket
is similar to that described except that there is no need for a recess or
projection to hold or grasp the ball. In smooth or rifled ordnance a spring
or elastic medium may occupy part of the cavity above mentioned between the
recess and projection in the jacket and ball, or vice versa, I also cause the
jacket to rotate by cutting or forming thereon or therein spiral grooves, lines,
or channels of a particular form, or wider at one end than at the other, or
having, when the jacket is in the gun only, a slight connection with the
atmosphere in front of the jacket. The grooves, lines, or channels may reach
through or only partly through the jacket. Into these grooves, lines, or
channels the gas produced by the explosion will rush and so cause the jacket
to rotate; or such grooves, lines, or channels, may be cut for this purpose on
or in both the jacket and projectile in proper directions.
In any of the preceding cases, as well as when the projectile is used without
a jacket, the projectile itself may be formed of a core spirally winged, grooved,
lined, or channelled on its periphery and then surrounded by a separate casing
so fixed as to enclose partly or wholly the grooves or channels. In some
cases to lessen atmospheric resistance to projectiles I place a false bead or
front of a suitable form on or in the fore part of the projectile made of such
material and so arranged as to be readily destroyed by the impact of the shot
when it strikes.