Improvements in Projectiles.
Year: 1890

page_text: Date of Application, 29th Mar., 1890-Accepted, 10th May, 1890
A. K
COMPLETE SPECIFICATION,
Improvements in Projectiles.
I, DAVID MEFFORD MEFFORD of Toledo, in the State of Ohio, United States of;
America, at present residing at the Westminster Palace Hotel, London, in the
County of Middlesex, Gentleman, 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 :-
This invention relates to projectiles for heavy and light ordnance and fire arms
which may be carried into practice as follows:-
The projectile may be of the ordinary cylindrical shape, flat at the rear end and
conical at the other, and is preferably made a working fit in the barrel. The
invention will be best understood by reference to the accompanying drawings in ;
which,
Figure 1 is an elevation of the projectile with a portion of the gun barrel in
section;
"
Figure 2 is a longitudinal section of a portion of the projectile ;
Figure 3 is a similar view to figure 2, and
Figures 4, 5 and 6 are views of the lugs or projections which fit into the rifle..
grooves of the barrel.
Like letters represent similar parts in the various figures.
A represents the body of the projectile, and B the gun barrel; C the rifle grooves
in the. barrel and D the lugs or projections which travel therein. The projectile as
shown is provided with one or more grooves or annular recesses E placed between
the two rows of lugs which latter as shown may be located, the one row at the rear
of the projectile and the other at the forward end of its cylindrical portion. These
grooves E are intended to act as a gas check and for this purpose are made large
and deep, somewhat as shown in the drawings. As shown in figs. 1 and 2. the
forward face of each groove is recessed as at E¹ or bevelled for the purpose of
directing the air or gas as it is forced into the groove back again with what may :
he termed a cyclonic action so that it may itself tend by its rebound or backward
action to prevent the passage of the gas beyond that particular groove.
With a
view to increasing this effect the shape of the grooves may be varied and they may
for example be shaped as shown in fig. 3, which may be described as an exaggeration":
of the shape of figs. 1 and 2, and which is done with the same object, viz., to impart
a reverse movement to the gas.
Placing the grooves where shown and making them so large is also important as
tends to improve the balance of the projectile as it travels through the air.
Commonly the projectile when discharged from a gun does not maintain the same
axial line but the ends are apt to gyrate around the-true-axial-line with the effect
of destroying the accuracy of the course travelled, and also causing the projectile to
strike with any part rather than its pointed end. By however my present invention
I make the rear end of the projectile lighter than the forward end so that the centre
of gravity would be nearer the front than the rear of the projectile and thus get rid
of the over weight at the rear. It will thus be seen that two very important functions
are served by making the grooves E so large proportionately to the size of the
projectile. In the first place ample space is provided for the return movement of
the gas, and in the next place by removing so much metal the projectile is lightened in
the very part where it is most required. Another advantage arises in consequence
of the large size of the grooves and that is that the sabot or rear of a projectile is
not infrequently "jumped up" or spread out by the force of the powder exploding
behind it, but with the large grooves E and the consequently small diameter of
the projectile at that part the jump effected instead of taking place on the full

page_text: diameter of the projectile as has hitherto been the case will take place in the
weaker portion, viz., the small diameter where it will do no harm.
By reference to fig. 1 it will be seen that the projections or lugs D on the forward
and backward rows are not placed in the same axial line, but that if the rear lug be
upon the line, the forward lug will be off it; this arrangement is adopted to meet
the curve of the rifle grooves in the gun barrel and the extent of difference in
position between the two lugs will depend upon the quickness or otherwise of the
curve in the grooves. By this arrangement I am able to dispense with the copper
rings usually placed upon the sabot and on other portions of the projectile and which
have to be cut by the edges of the rifle grooves as the projectile is started on its
course. This tearing away of the copper is an objectionable feature and causes the
projectile to jam more or less in the barrel, besides tending to coat the grooves with
copper and thus prevent the next projectile from working so freely; this difficulty is
overcome by my present arrangement.
In figures 4, 5 and 6 I show the surface of the lugs or projections reduced at their
forward edges as at D¹; the object of this is to present a sharp edge to the groove so
as to clear it of any obstructions or dirt that may have accumulated therein. The
edge may be cut straight across as in figure 4 or curved like a crescent as in figure 5,
in which latter case the tendency is to collect any obstructions within the recessed
portion of the lug which may have a flattened edge or surface so as to present a
sufficient hold to the walls of the grooves.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I wish it to be understood.
that I am aware that it has before now been proposed to form grooves on the sabot
of a projectile for the purpose of acting as a gas check but that such grooves have
been exceedingly small, too small to be of practical utility and were improperly
placed on the projectile. What I claim is :-
1. The complete projectile substantially as described and illustrated in Fig. 1 of
the accompanying drawings.
2. A projectile having grooves such as E located and arranged substantially as and
for the purpose described and illustrated in the accompanying drawings.
3. A projectile in which the forward half or portion is heavier than the rear half or
portion.
4. In a projectile a groove such as E for the double purpose of serving as a gas
check and lightening the projectile at that part.
5. In a projectile a stepped lug or projection such as D D' substantially as and for
the purpose described and illustrated in the accompanying drawings.
Dated this 26th day of March 1890.
DAVID MEFFORD MEFFORD.
W. P. Thompson & Boult,
Agents for the Applicant.