Improvements in Projectiles.
Year: 1889

page_text: COMPLETE SPECIFICATION.
Improvements in Projectiles.
I, SELDEN ALLEN DAY, of Bowling Green, Wood County, in the State of Ohio,
United States of America, Captain in the United States Army, do hereby declare
the nature of the said invention and in what manner the same is to be performed to
be fully described and ascertained in and by the following statement :-
This invention relates to projectiles for fire-arms including either small arms or
ordnance, the invention being applicable to bullets, solid shot and explosive
shells.
My improved projectile is designed especially for use in fire-arms the bore of which
is rifled in order to impart a rotary motion to the projectile during the act of firing.
The objects of my invention, are to impart an accelerating rotary motion to the pro-
jectile, thereby overcoming its inertia gradually and accomplishing the purpose of
an "increasing twist" rifling without incurring its disadvantages, and to provide for
the more thorough and effective lubrication of the bore than has heretofore been
accomplished.
To this end my improved projectile is constructed with a body portion of any
suitable proportions and with a separate base or sabot connected to it through the
medium of a screw-thread and normally partly unscrewed. The body of the pro-
jectile is formed of a mass and consequently has an inertia greatly in excess of that
of the base. The body of the projectile is made of slightly smaller diameter than the
bore of the gun so that it shall rest upon the lands or spaces between the rifle grooves,
while the base or sabot is made of larger diameter or is formed with exterior ribs of
any known pattern so that it shall engage the rifle grooves. When the projectile
with the base partly unscrewed is placed in the rifled bore of the fire-arm and fired
the inertia of the body of the projectile causes it to resist the rotative tendency of the
rifling, while the base being engaged by the rifles is rotated and consequently is
screwed up to the body portion, so that before the projectile leaves the gun the
base has been fully screwed up and its rotation is communicated to the body of
the projectile. The friction of the screw-threads, increased by the propulsive pres-
sure transmitted to the body portion through the base, imparts a continuous rotative
tendency to the body portion which gradually becomes effective in rotating the
body portion as it overcomes the inertia thereof, so that the body of the projectile
during its travel through the bore of the gun receives an accelerating rotary motion
which with the best proportions should nearly equal the speed of rotation of the base
or sabot at the instant that the latter becomes screwed tightly against the body, which
should occur just before the emergence of the projectile from the gun, so that at the
time of passing out of the bore the base and body are rotating together at a uniform
speed.
In a space or cavity between the partly unscrewed base and the body a mass of
lubricating substance is placed which by its presence further resists the screwing up
of the base and serves thus to impart a rotative tendency to the projectile body, and
which serves the further purpose of lubricating the bore of the gun by being squeezed
out thereinto by reason of the screwing up of the base. As this screwing up takes

page_text: place continuously during the travel of the projectile through the bore, the squeezing
out of the lubricant occurs also continuously, so that approximately a uniform quantity
of lubricant is spread upon the surface of the bore during the entire travel of the pro-
jectile. The arrangement is such that the lubricant thus expelled is discharged in
advance of the base or sabot.and consequently enters. between the latter and the rifle
grooves and lands so that the lubricant is applied at the exact time and place that it is
needed, and each projectile lubricates the bore for itself instead of for the succeeding
projectile.
S.
My invention also relates in part to explosive shells especially adapted for firing
dynamite or other high explosives, its objects being to prevent the premature ex-
plosion of the cartridge by protecting it from the direct-transmission to it of the shocks
to which the shell or projectile may be subjected in transportation, handling and firing
while providing if desired that the shock of impact of the projectile upon striking its
target shall suffice to explode-the-charge: To this end I form the projectile or shell
with a hollow chamber extending longitudinally of it, within which the cartridge or
capsule of explosive is placed in such manner that it is free to move longitudinally
therein being seated against springs at its opposite ends to transmit shocks to it
elastically, and the chamber being filled with glycerine, water or other suitable liquid
to impede and retard the movement of the explosive cartridge within it. The direct
contact of the cartridge with the walls of the chamber is prevented by means of small
lugs or projections formed on or applied to, one part or the other, whereby the cart-
ridge is held centrally within the chamber and a free space is maintained on every side
for the flow of the surrounding liquid.
I have shown in the accompanying drawings several different embodiments of my
invention.
.
Fig. 1 is a side elevation of an explosive shell embodying all the features of my
invention, the shell being partly broken away in longitudinal mid-section in order to
show the enclosed cartridge or capsule of explosive material and its seating.
Fig. 2 is a longitudinal mid-section thereof.
Fig. 3 is an end elevation thereof.
Fig. 4 is a transverse section on the line 4-4 in Figs. 1 and 2.
Fig. 5 is an elevation of the explosive cartridge and its seating springs removed.
Fig. 6 is a fragmentary elevation partly in mid-section, showing a slightly modified
construction of the screw base.
Figs. 7 and 8 show a modified construction designed more especially for small arms,
Fig. 7 being a longitudinal mid-section of the projectile with its parts assembled, and
Fig. 8 being an elevation showing the parts separated.
.
Figs. 9, 10, and 11 show another construction applicable to either large or small
arms, Fig. 9 being a side-elevation, Fig. 10 a longitudinal mid-section, and Fig. 11 an
elevation of the screw-base removed.
.
Figs. 12, 13 and 14 are elevations partly in longitudinal mid-section of different
constructions of the screw-base or sabot.
Fig. 15 is a longitudinal mid-section of a projectile designed to be shattered or
splintered in all directions upon striking its target.
Fig. 16 is a longitudinal mid-section of an explosive shell having a percussion fuse
adapted to explode upon striking.
Referring to the drawings, let A designate the body of the projectile and B the
screw-base or sabot. The body A comprises by far the greater portion of the weight
of the entire projectile. The base B is united to the body A through the medium of
male and female screw-threads a, the sabot being normally partly unscrewed and the
intervening space thus formed being filled with lubricating material designated at C
and C. The projectile body A is made of such small diameter that it is not engaged
by the rifle grooves but rests upon the intervening lands. The base B is made of
somewhat larger diameter so that it enters the grooves or is formed with ridges or
projections which take the grooves. The base or exterior portion thereof which takes
the rifle grooves is constructed by preference of soft metal..
Having thus in general described my invention without special reference to any one

page_text: of the constructions shown I will now proceed to describe more particularly the several
different constructions illustrated in the accompanying drawings.
Figs. 1 to 5 inclusive illustrate an explosive shell designed for the purposes of
penetration and subsequent or simultaneous explosion. The rear portion of the pro-
jectile body A is formed with a neck or tail having male screw-threads a a cut upon
its exterior. The base B is formed as a screw-cap having interior or female screw-
threads adapted to screw upon this neck. The screw-threads should be of somewhat
steep pitch, a double thread being preferably used. When the base is partly screwed
on, two cavities or spaces are formed which are filled with lubricant, the one being the
space within the cup against the end of the screw-threaded neck b, and the other the
annular space or groove around the exterior of the neck band between the front edge
or flange of the cup and the shoulder formed by the contraction of the neck. The
latter of these spaces is filled with a mass of lubricant lettered while the former is
filled with lubricant lettered C. The lubricant may be tallow or any kind of grease,
wax, or a mixture of tallow or wax with graphite, or it may consist of some absorbent
material saturated with oil. The lubricant at C is preferably a mixture of tallow and
graphite or an absorbent, such as felt, saturated with oil, while that in the space ("¹
As the
may be a mixture of tallow and graphite or any suitable grease or wax alone.
base B is screwed up by the action of the rifle grooves in firing, the lubricant is
squeezed out, that at C being delivered to the bore of the gun just in front of the pro-
jecting portion or luting c of the base, which is preferably made of soft metal to enter
the rifles, while the lubricant C is squeezed out through holes or openings dd. The
base B is preferably constructed of hard metal in which the screw-thread is formed
and its outer or projecting portion c is a luting of soft metal applied to it in any
suitable manner, as for example, in the manner shown in Fig. 2, where the tubular
luting of soft metal comes against a shoulder near the front of the cup-shaped base.
The soft metal luting preferably projects beyond the rear face of the head B in
order to form a cup-packing to be expanded into the grooves by the gaseous pres-
sure in firing, on the principle of the expanding sabot of the Parrott shell. This
construction of the base B, however, may be greatly varied, one example of which
is shown in Fig. 6, where the entire base is formed of one piece of suitable metal
screwing directly on the neck 6 and formed with holes d d for the discharge of the
lubricant. The lubricant instead of being provided both at C and C inay be
omitted in either one of these places. In Fig. 6 the lubricant is shown applied
only at C¹.
The construction of the base and its screw connection shown in these figures is
that which is preferable for an explosive shell wherein the projectile body A is
made hollow to form a chamber for the explosive. In the construction shown the
shell is provided with a conoidal point section A¹ screwed or otherwise fastened
into the open front end of the body, which is bored out or otherwise hollowed to
form a chamber D.which is filled with glycerine, water, or other suitable liquid.
Within this chamber is placed a capsule or cartridge E containing the explosive,
which may be dynamite or other high explosive. This capsule is retained in the
middle of the chamber D by some small projections or lugs e e at intervals which
may be formed integrally with the body A, as shown, or otherwise. Their function
is solely to keep the capsule out of contact with the walls of the chamber in order
to permit the liquid to circulate freely on all sides of the capsule, forming a sort
of liquid cushion in which the capsule is immersed. Springs and fare arranged
against the opposite ends of the capsule, being compressed by the screwing in of
the point A and serving to form an elastic seat for the capsule in order to transmit
to it gently the shocks to which the shell may be subjected in handling, loading
and firing and to prevent the transmission to the capsule of any such severe
shocks as will suffice to explode the shell. The spring, which is the longer of
the two, comes against the rear of the capsule and serves partially to take up the
inertia of the capsule in firing. At such time the capsule has à relative backward
movement longitudinally within the chamber, whereby it compresses the spring f
which thus somewhat rosists the movement of the capsule due to its inertia. This

page_text: relative movement is, however, principally resisted by the surrounding liquid which
must necessarily flow from the space in the rear of the capsule along the sides
thereof into the space in front of it, and this flow of the liquid, being accompanied
by some degree of friction, exercises a retarding influence on the capsule.within
the shell. In addition thereto, the liquid bas another important function, in that
it serves to absorb heat generated by the resistance of the shell and capsule to the
force of propulsion due to their inertia.
:
That part of my invention which comprises the screw-base B and the means for
lubrication, although admirably adapted to the construction of an explosive shell is not
limited in its application thereto, but may be applied to solid shot for ordnance or
bullets for small arms. Figs. 7 and 8 show a construction applicable to either large or
sinal projectiles. The body A is formed with a screw-neck b, which is somewhat
prolonged, and on which are screwed one or more nuts, two nuts B and B₁ being
shown. Á lubricating washer C is shown as interposed between these two nuts, and
another washer (between the nut B and the shoulder at the front of the screw-
threaded neck. The forward nut B' may be of the same diameter as the body A so
that it will not take the rifle grooves, but the rear nut B is provided with an exterior
luting of soft metal c, whereby it is constituted the screw-base or sabot before referred
to, there being, however, this difference between this base and that shown in the
preceding figures, that it is not in the form of a cup since the screw-neck projects
entirely through it. The washers CC² are preferably loose felt saturated with oil or
impregnated with grease or wax. When the projectile is fired the base B is first
screwed up by the rifling, thereby foreing out the lubricant C, after which the nut B¹
is screwed up, forcing out the lubricant (2. If additional nuts are used they will be
screwed up successively.
Figs. 9, 10 and 11 show another construction wherein the female screw is formed
in the body A and the male screw is applied to the base B. This base is formed with
a screw-neck or shank the male threads a on which engage female threads a¹ in a
tapped hole in the rear of the projectile body A. The soft luting is preferably a
cup-shaped piece of copper forced over the base B. The lubricant is a mass of tallow.
and graphite or a washer of oiled felt arranged at C.
Figs. 12, 13 and 14 show different constructions of the base B in respect of the soft
metal sabot luting c. In Fig 12 this luting is shown cupped and of the same diameter
as the head of the base B, being designed to be of the same diameter as the projectile
body A so that it shall not enter the rifle grooves until expanded thereinto by the
internal pressure of the gases after the manner of the sabot of the Parrott shell. Such
construction is well adapted for muzzle-loading guns. In Fig. 13 the soft metal c is
confined between two flanges or shoulders and while in Fig. 14 it rests against a
flange i at the front and is formed with a rabbet which conceals this flange.
Figs. 15 and 16 illustrate a construction of my invention which is well adapted for
certain purposes. The body A of the projectile is made of a tube of the proper
diameter and having a bore of such size that when a screw-thread is tapped into it a
little ways at its rear and the screw-neck b can be screwed thereinto sufficiently to
form a firm connection therewith, leaving a sufficient length of the screw-neck pro-
truding to form the connection for the nuts B and B1, which in both these figures are
shown as of the same construction as in Fig. 7. This forms a cheap construction
since the body A and screw-neck can be cut off from long lengths respectively of"
steel tube and of screw-threaded steel rod and put together by machinery. The cavity
formed by the bore of the tubular body may be utilized either in the construction
of an explosive, shell of the character shown in Figs. 1 and 2, or in any other
preferred way.
In Fig. 15 I have shown this bore filled with soft metal H, the mass of which
projects at the front and is moulded into conoidal form to constitute the tip of the
projectile, the front end of the tubular body A having previously been internally
beveled or countersunk at j in order that the soft metal filling H may form a conical
wedge which upon the striking of the projectile will be driven back into this counter-
sink, and by reason of the bevil thereof and by the lateral expansion of the soft metal

page_text: within the tube will split the latter into fragments which will fly or penetrate in all
directions. This construction has also the advantage that the greater weight of the
soft metal increases the range of the projectile, and by the massing of the soft metal
in the tip H the centre of gravity is brought nearer the front. If a penetrating
instead of a splintering projectile is desired, the countersinking at i may be omitted,
the hard-metal tube being made with a square front end. In such case the hard-metal
tube gives stiffness to the projectile, while the soft-metal filling and tip impart weight.
In Fig. 16 the bore of the tubular body is shown filled with powder or other
explosive G and with a percussion cap or fuse J at the tip designed to be exploded by
the striking of the projectile and to fire the explosive charge G.
My invention by a simple and inexpensive construction of the projectile realizes the
important practical advantage of imparting to the projectile an accelerating rotation
without resorting to the expedient of rifling the bore of the gun with an increasing
or "gain twist." My projectile is designed to be fired in barrels having a rifling of
uniform twist. The disadvantage of such rifling heretofore has been that the inertia
of the projectile usually causes it to resist at starting the rotative movement which the
twist imparts, so that until this inertia is overcome it is being forced forwardly through
the bore with a slower rotative movement than that corresponding with the pitch of
the rifling, so that in this case the metal of the projectile is torn off by being forced
across the rifle levels, thereby injuring both the projectile and the gun. To overcome
this obvious difficulty the employment of an increasing or gain twist" bas been
resorted to, but with no very satisfactory results, such a twist being found to have the
disadvantages that it tends to rotate the front of the projectile at a more rapid
speed than the rear portion thereof, and that it twists and distorts the projectile
in such a way that it materially increases the friction in its passage through the
bore. These difficulties have increased with the change that has taken place in the
proportions of projectiles in the direction of an increase of their length in pro-
portion to their calibre.
፡፡
With my improved projectile the theoretical advantages of the increasing twist
are realized in the use of a gun rifled with a uniform twist, since the inertia of
the projectile is overcome gradually, the screw-base being of very little weight
and affording consequently, very slight inertia-being caused to partake immediately
of the rotary motion due to the pitch of the rifling, and this motion being gradually
communicated to the projectile body. By the use of my invention a rifling of
more rapid twist can be employed than has been hitherto practicable. This constitutes
an important desideratum in view of the present tendency toward the reduction of
the calibre and the necessary increase of the length of the projectile, it being well
known that the greater the length of a projectile in proportion to its calibre the
more rapid revolution it requires to cause it to fly end on. My invention also
possesses very important advantages in the thorough and effective lubrication of
the barrel, whereby the injury of the projectile in being fired is prevented and
the undue heating of the barrel and the cutting of the rifle grooves and lands is
avoided.
The portion of my invention which relates to the lubrication may be omitted
while retaining the advantages inherent in the screw-base or sabot, but in such case
it is preferable to substitute for the mass of lubricant some other similar resisting
substance or device for communicating from the base to the projectile body the
rotary tendency. This rotary movement may be communicated solely by the
friction of the screw-threads, but it is preferable to make the screw-threads as nearly
frictionless as possible and to substitute some sufficiently resisting material or element
for thus communicating the rotation.
I am aware that it has been proposed to mount a cartridge of explosive material
within a cavity in a shell, and to cushion it on springs. And I am aware that in
another instance it has been proposed to arrange an explosive cartridge within a shell,
with a filling of liquid in the intervening space. But in neither of these instances has
the explosive cartridge or capsule been free to nove longitudinally in the cavity,
with the combination of springs tending to hold it in place and resist its movement,

page_text: and a surrounding liquid which must flow from the space at one end of the cartridge
along the sides thereof to the space at the other end, and which thereby acts to retard
the movement of the cartridge due to its inertia.
Having now fully 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. My improved projectile characterized by the separate base or saboi connected to
it through the medium of a screw-thread, normally partly unscrewed, and constructed
to be rotated by the rifle-grooves in firing, and thereby to be screwed up against the
body of the projectile, and while it is screwing up to gradually impart rotation to
the body.
2. Applying a lubricating substance between the base and body of the projectile, so
that the lubricant is gradually squeezed out by the screwing up of the base.
3. My improved explosive shell, characterized by enclosing a capsule E of explosive
in a chamber D in the projectile, with a filling of liquid in said chamber to retard the
relative movement of the capsule, springs ff to return the capsule to its normal
position, and projections e e for keeping the capsule in the centre of the chamber.
4. The improved construction of projectile shown in Fig. 15, in so far as the same is
characterized by the hard-metal outer tube with a filling of softer and heavier metal
within said tube and extending beyond the front thereof to form the tip, whereby the
tube imparts stiffness and strength and the filling imparts increased weight and
consequently increased range and penetration.
5. The improved construction of shot or bullet shown in Fig. 15, characterized by
the hard-metal tube having the coned front end j and the soft-metal filling or tip Ĥ
adapted to be driven back and expanded laterally upon striking, and thereby to split
open or splinter the hard-metal tube.
Dated this 27th day of Septembar 1900
J. C. MEWBURN,
55 & 56, Chancery Lane, London, Patent Agent.