Improvements connected with Fire-arms using Rimless Cartridges.
Year: 1892

page_text: COMPLETE SPECIFICATION.
Improvements connected with Fire-arms using Rimless Cartridges.
I, MURRAY HAINES DURST, of Wheatland, in the County of Yuba and State
of California, United States of America, 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 breech-loading fire-arms especially adapted for using
the so-called "rimless cartridges"; the object being to provide means for properly
locating the cartridge within the barrel prior to firing the same, for overcoming
the transverse breakage of the shells, and for insuring against missfires and failure
of extractor hook to engage over the rim of the cartridge.
In the drawing accompanying and forming a part of this Specification.
Figure 1 is a side elevation of a portion of a breech-loading gun embodying my
present improvements.
Figure 2 is an end elevation of the parts shown in Figure 1, as seen from the
right-hand in said figure.
Figure 3 is a sectional side elevation, on line cd Figure 2 and showing the
rimless cartridge in place in the gun ready for firing.
Figure 4 is a view similar to a principal portion of Figure 3, illustrating the
operation of my improvement.
Figure 5 is a sectional plan view partly on line ab of Figure 2 and illustrating
certain features of my invention.
Figure 6 is a sectional elevation similar to Figure 4, illustrating a modification
of the invention.
Figure 7 is a sectional elevation similar to Figures 4 and 6, illustrating a further
modification of the invention.
Figure 8 is a side view of the form of cartridge-stop shown in Figures 3, 4, and 5.
Figure 9 is a plan view of the under side of said stop.
Figure 10 is an end view of a band for holding in place the cartridge-stop shown
in Figures 3, 4, 5, 8, and 9.
Figure 11 is a plan view of the stop-actuating spring shown in Figure 7.
Similar characters designate like parts in all the figures.
It will be remembered that in using the so-called "rim cartridges" heretofore
more generally employed, it has been customary to limit the entering movement of
the cartridge into the chamber of the gun-barrel by means of the rim of the
cartridge striking against the rearward end of the barrel, the cartridge being forced
into the barrel by the bolt of the gun. According to that arrangement, of course,
the cartridge is accurately located by the clamping of its rim between the, rearward
end of the barrel and the forward end of the bolt, so that no space would exist, at
the moment of firing, between the rearward face, or head, of the cartridge and
the bolt. According to the old plan therefore, the particular length of the cartridge,
measured from the head thereof to the forward shoulder at the base of the projectile,
was not important within moderate limits; nor could the firing-pin, when striking
the cap, drive the cartridge forward in the barrel, since the rim of the cartridge
positively limited the entering movement thereof.
In using the rimless cartridges, however, since the diameter of the heads of the
same is equal to, or less than, the diameter of the rearward end of the shell, it has
been customary to rely upon the forward shoulder 3 of the cartridge coming against
the corresponding face, or shoulder 4 of the barrel to prevent the cartridge from
going too far into the bore of the gun. In practice, it has not been found practicable
to precisely locate the cartridge in the barrel by means of said shoulder, since the
length 20 (Figure 4) between the rearward face of the cartridge 2 and its shoulder 3
TD Q77

page_text: varies by an appreciable amount, so that, accurately speaking, the rimless cartridges
are of various lengths. When the rimless cartridge is driven forward into the
barrel, the obvious tendency of it is to go forward against the barrel-shoulder 4;
and if the cartridge is shorter than its normal or proper length 20, this will leave
a corresponding space between the head of the cartridge and the bolt. Also, the
effect of the firing-pin, when this is thrown forward, is to drive the cartridge its
full length into the barrel, thereby increasing the space between the cartridge-head
and the bolt to the maximum amount. If now the cartridge be fired, the first
effect of the explosion is to expand the shell within the barrel until this bears
against the inner surface of the chamber with such force that the pressure of the
gases longitudinally of the shell, even after the bullet has been expelled, is not
sufficient to slide the shell back in the chamber, but throws the entire longitudinal
force of the explosion into the shell at a point near the rearward end thereof. In
practice, this enormous force is sufficient to tear asunder the cartridge-shell at
about the line m, Figure 3, leaving the forward portion 7¹ thereof in the barrel
when the bolt is retracted, only the rearward portion 71 of the shell being
extracted.
The object of my present invention is accomplished by the provision of means
for limiting the entering movement of the cartridge into the barrel, so that the
head thereof will bear properly against the bolt at the moment of firing.
The breech-loading gun, partially shown in this application, has the usual
barrel, 6, which is bored or chambered at its rearward end to receive the
cartridge 7, and is fitted to be screwed into the forward end 8 of the receiver, or
frame, 23, of the gun. Said frame is shown provided with a longitudinally-
reciprocating bolt, which may be of any suitable and well-known construction.
As herein shown, the bolt consists of the principal portion or part 9, having the
forwardly-extending part 10 fitted to drive the cartridge into the bore of the gun,
and support the same when fired. The bolt mechanism is shown provided with the
usual firing-pin, 11, actuated by a spring, 12, only partially herein shown.
Figure 3, the firing-pin is shown retracted, and in Figures 4, 5, 6, and 7, it is shown
thrown forward as when the gun has been fired.
In
In Figure 5, the usual extractor, 13, is shown carried by the bolt 9, and having
its hook, 131, engaging in the recess, or groove, 14, forward of the head, 15, of the
cartridge. In this connection it will be observed that one of the advantages of my
present improvements, is that by limiting, as set forth, the entering movement of
the cartridge into the barrel, the head 15 of the cartridge is prevented from going
forward of the extractor-hook, which would thereby be rendered inoperative to
extract the cartridge when the bolt is retracted. This feature also obviates the
necessity, in manufacturing the ammunition, for so closely gauging the thickness of
the cartridge-head; and in general, my improvements secure much more perfect
results with the use of less perfectly made cartridges.
For limiting the forward movement of the cartridge when this is driven into the
bore of the 'barrel, I provide the fire-arm with a cartridge-stop operable trans-
versely of the cartridge for engaging the same to limit the entering movement
thereof. This stop, designated in a general way by 16, is shown in Figures 3, 4,
5, 8, and 9, carried at the rearward end of the spring 17, whose forward end is
enlarged, and held in place, by means of the band 18, in a recess in the gun-barrel.
The stop 16 is shown in said figures fitting in a notch in the rearward end of the
gun-barrel, and is adapted, by reason of its being carried by the spring as aforesaid,
to have a movement transversely of the cartridge for permitting the body of the
cartridge-shell to pass the same, and to engage in the groove, or recess 14, forward
of the head 2 of the cartridge when this is driven into place as in Figures 3, 4, 5,
6, and 7.
When the cartridge is started into the barrel, the side of the shell impinging
against the inner end of said stop, drives this outward; and when the recess comes
to the stop, this is thrown in radially by the spring to firmly engage the cartridge
head, as also indicated'in said figures.

page_text: In Figure 6, the construction of the stop and its actuating spring 17 is the same
substantially as shown in Figures 3, 4, and 5; but in this case, said spring has
connected thereto a forward extension or spring 38, which fits closely between the
forward end of the receiver and a notch at 19, in the barrel, whereby the stop-and-
spring is held in place, and also a more free action thereof obtained by reason of
the two connected springs 17 and 38.
In the modification shown in Figure 7, the stop 16 is constructed to slide
radially of the gun-barrel in a notch at the rearward end thereof, being limited in
its sliding movement_transversely of the cartridge by the stop 21 working in the
space or recess 22. For actuating this stop to engage the cartridge, the receiver 23
is provided with a spring 17, whose rearward end has a pin 24, bearing upon the
outer end of said stop, and whose forward end is attached to the receiver by means
of a screw 25, see Figures 7 and 11.
The operation of these modified forms of my improvement is substantially the
same as the operation of the form thereof, herein before first described.
One advantage of my present improvement in fire-arms for using the ammunition
specified, is that the shoulder 4 of the barrel may be made somewhat in advance
of the normal position of the shoulder 3 of the cartridge, leaving a space 3',
Figure 3, for the disposal temporarily of any dirt which may be upon the cartridge-
shells, or which may be carried forward in the barrel on the insertion of the shell.
On firing the gun, the pressure of gases within the shell expands the same to fill
said space 31, as indicated in Figure 4; but this action of the shell does not
ordinarily, in practice, burst the same or otherwise interfere with the extraction
thereof.
In the combinations shown in Figures 1 to 6 inclusive, the stop 16 and its
carrier-spring are covered by the forward end of the receiver, into which the barrel
is fixed, said stop and spring lying in the recess 28, formed therefor in the barrel.
By means of this construction, the stop is safely held from being blown out of the
gun while firing cartridges having defective shells, the outward movement of the
stop being, in such cases, limited by the upper wall 27, of the receiver, or frame,
of the gun.
Figures 12, 13, 14, 15, and 16 show an alternative construction of the cartridge-
stop, which consists of a lever or stop a pivoted at c in the receiver frame, so that
the front jaw a will have a motion into the chamber of the barrel. It is operated
by the travel of the bolt 10. As the cartridge goes into the chamber, the stop is
forced out, and just as the bolt reaches home, the shoulder d comes in contact with
the jaw b of the stop, and forces the jaw a down into the cannelure of the cartridge,
and holds it there.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
1. In a breech-loading gun for using rimless cartridges, the combination with the
barrel, and means for delivering the cartridge to the barrel, of a cartridge-stop
operable transversely of the cartridge for engaging the same to limit the entering
movement thereof, substantially as described.
2. In a breech-loading gun for using rimless cartridges, the combination with
the barrel, of a cartridge-stop interposable into the cartridge-chamber, and a spring
for actuating the stop to force the same into the said chamber, substantially as
described.
3. In a breech-loading gun for using rimless cartridges, the combination with the
barrel, of a movable stop, means for normally projecting the stop into the barrel,
the reciprocating bolt, and the cartridge-extractor carried by the bolt, substantially
as described.
4. In a breech-loading gun for using rimless cartridges, the combination with
the barrel and the reciprocating bolt, of the movable stop, a spring carrying said

page_text: stop at one end thereof, and means for holding the spring in place, substantially
as described.
5. In a breech-loading gun for using rimless cartridges, the combination with
the barrel having a recess therein for the stop and its carrying spring, of the stop,
the spring carrying said stop, and the receiver covering the spring, and limiting the
outward movement of the stop, substantially as described.
6. In a breech-loading gun for using rimless cartridges, the combination with
the barrel having the recess for the stop and its carrying-spring, of the stop, the
spring carrying said stop, the receiver carrying the barrel, and covering said
stop, and the band holding the spring to the barrel, substantially as described.
7. Arranging a hinged stop in the receiver, or barrel, so as to have a motion
transversely of the cartridge, and operable by the travel of the bolt to engage in
the cannelure of the cartridge, as and for the purpose specified.
8. A spring, or hinged stop 16 in recess 28 of barrel 6 or of breech ring 23 of
fire-arm for engaging in cannelure of rimless cartridges, and limiting the distance
of entry into the barrel 6, as and for the purposes set forth.
Dated this 16th do of Now 1000
H. GARDNER,
Patent Agent, 166, Fleet Street, London,
Agent for the said Murray Haines Durst.