Year: 1888

page_text: 1 ABRAHAM MARTIN, of 177 Aston Lane, Witton near Birmingham Engineer
do hereby declare the nature of this invention to be as follows:-
This Invention relates to the manufacture of cartridges for small arms and machine
guns.
The cartridges are of that kind for which a solid drawn metal cartridge case is
employed and which are filled with a solid compressed explosive charge. Such
charges are necessarily introduced at the base end of the case owing to the taper form
of the latter and the means heretofore adopted of closing the base end of the case
after the introduction of the charge have not been effectual to prevent the escape of
gas at the joint. This joint is therefore a source of weakness inasmuch as the base of
the cartridge does not afford any support to the sides against the expansive pressure
of the gases.
My Invention has first for its object to afford all the strength and absence from
leakage of the ordinary metallic cartridge case in which the base is in one with the
sides of the case; and it consists in substituting for the plug base heretofore used, an
inner solid drawn case having its cylindrical portion and base in one solid piece of
metal and adapted to fit friction tight within the open base of the cartridge case now
used. This inner case is of such length as to wholly or partially contain the com-
pressed charge which is thus virtually surrounded by a double metallic cartridge case.
This inner case is expanded by the internal pressure of the gases and so renders the
joint between itself and the outer case absolutely gas-tight.
My Invention has further for its object to fix the bullet in the cartridge case. Here-
tofore, the bullet has been inserted at the open front end of the cartridge case, and if
necessary has been made to fit the same by a wrapping of paper around the bullet

page_text: which is a troublesome operation. The bullet is moreover, but insecurely held and is
apt to fall out with ordinary usage.
My Invention consists in introducing the bullet from the open base end of the
cartridge, the front end of the cartridge, case being by preference slightly tapered so
that when the bullet is driven through it into position, it will be tightly held. The
bullet may be either tapered or not, the case, if parallel, expanding to correspond to
the form of the bullet as the latter is driven through it.
Dated this 22nd day of September 1888.
A. MARTIN.
By A. M. & Wm. Clark,
53, Chancery Lane, London,
Patent Agents.

page_text: COMPLETE SPECIFICATION.
Improvements in Cartridges.
1 ABRAHAM MARTIN, of 177 Aston Lane, Witton, near Birmingham, in the
County of Warwick England, Engineer, do hereby declare the nature of this inven-
tion 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 the manufacture of metallic cartridges for small arms
machine and other guns for which such cartridges are used. The cartridges are of
that kind for which a solid drawn metal bottle shaped cartridge case, especially
adapted to be filled with a solid or compressed explosive cbarge, is employed. Such
solid charges are necessarily introduced at the base end of the case owing to the
bottle-like form of the latter and the joint between the part by which the base
end is closed and the sides is liable to leakage under the expansive pressure of the
gases.
Reference is to be had to the accompanying drawings forming part of this specifi-
cation in which figure 1 represents a longitudinal section of a bottle shaped cartridge
constructed according to my invention, and figure 2 shews the two parts of the case
separately. The same letters of reference serve for like parts in both figures.
My Invention has for its object to afford all the necessary strength and perfect
absence from leakage; and it consists of an inner solid drawn sheath or case a a¹
having its cylindrical portion a' and base a in one piece of metal and adapted to fit
tightly within the open base end and cylindrical part of a solid drawn cartridge
case. This inner case or sheath a a¹ is of such length as to wholly contain the solid
or compressed charge e which, when thus ensheathed and introduced into the outer
principal case 6 is surrounded circumferentially by a double metallic cartridge
case.
The inner sheath or case a a' may be made of the same metal as is generally used
for the outer case b, but it is preferably softened at its open end by being annealed
whilst the outer case may be drawn very hard to facilitate its extraction from the
gun; this combination of soft and hard metal adding considerably to the strength of
the case.
The base a of the inner case is of the ordinary form and is adapted to carry the
ordinary priming at the centre. It is stamped up of the form shewn and gradually
tapers off in thickness where it joins the sides a¹ which are rather thinner at the front
end than the outer case b, the two a¹ and b being together only about equal in
thickness to that of the ordinary case. The part a' may be cylindrical externally and
the part & cylindrical internally, but the part is usually very slightly conical whilst
the part al is cylindrical and enters freely about half-way into and is then forced
tightly therein so as to virtually form one solid structure therewith.
b
It is essential that the inner sheath a' should extend at least as far as, and abut
against, the shoulder b¹ so that it should be caused to adapt itself to the form of the
shoulder of the outer case by being compressed or upset inwardly at the mouth a*

page_text: as shewn in figure 1. This is effected by forcibly driving the inner case (which has
previously been filled with the solid or compressed charge whilst it was in the
straight form shewn in figure 2) into the outer case whilst the latter is supported in
a steel mould of corresponding form with a through aperture for the exit of the bullet
in case of accidental discharge. The open end of the inner case having been
softened by annealing, as above mentioned, becomes cramped or upset inwards on
meeting the shoulders of the outer case when thus forcibly driven in by end pressure
applied to its base.
Upon the discharge of the cartridge, the cylindrical part a¹ of this inner case tends
to become expanded by the pressure of the gases so as to make an absolutely gas-
tight joint with the outer case particularly at the point where the inwardly-cramped
mouth abuts, as above described, against the shoulder of the outer case.
The part a is provided with a coned flange d which fits into a corresponding seat d¹
in the end of b, which is flanged externally as usual.
In order to protect the cartridge from moisture and prevent oxidation of the metal
by the contact therewith of the explosive, it is preferable to wrap the charge in oiled
paper before introducing it into the inner case a a¹ and, to further exclude moisture,
the external surface of the part a' may be varnished before introducing it into the
case b.
It will be apparent that a cartridge constructed as above described will be safer and
more serviceable in use, since there can be no danger to fear from flaws in the metal
or other defects which are occasionally incidental to the manufacture of solid drawn
cartridges. This cartridge is also specially adapted for use in quick-firing guns of
larger calibres than are now being introduced.
I would have it understood that my invention is limited to bottle-shaped metallic
cartridges which are charged with a solid or compressed charge wholly contained
within an inner case which is driven into the base end of the outer tube until its
front end forcibly abuts against the shoulder of the said outer tube.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
The herein described metallic cartridge case constituted by the combination with
the bottle-shaped outer tube or case 6 of the inner case a a¹ wholly enclosing the solid
or compressed charge and fitting in, and making a tight joint with, the outer tube or
case, as specified.
1000
A. MARTIN.
By A. M. & Wm. Clark,
53, Chancery Lane, London,
Patent Agents.