Improvements in Breech-loading Fire Arms.
Year: 1893

page_text: The decision of the Chief Examiner, acting on behalf of the Comptroller, of the
22nd day of October 1894, allowed, under Section 18 of the Patents, &c.
Act, 1883, an Amendment of this Specification.
Improvements in Breech-loading Fire Arms.
I, THEODOR BERGMANN of Gaggenau, Baden, Germany, Gun Maker 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 and machine guns on the sliding
breech bolt system, Heretofore the breech-bolt-hus-nanally-been so looked as to
oppose no solid and rigid a resistance as possible to the rearward gas pressure in
order that after-complete-utilization of their pressure the gases could only escape in
a forward direction, the breech bolt being unlocked-after each shot by hand or
mechanism or, in other movable bolt-systems, by the gas pressure and being locked
by hand or special devices or automatic means after reloading.
My invention and of that kind in which the retention of the breech bolt in the
closed position is based upon the principle of inertia whereby the locking of the
bolt is entirely dispensed with. As the pressure of the gases generated by the
explosion of the charge acts uniformly in every direction and as by the law of
inertia the smaller the mass of the movable body subjected to this pressure the
more rapidly it will be set in motion; then if the weight of the breech bolt is a
certain multiple of that of the projectile it will be set in proportionately slower
motion. If then the weight of the breech bolt be so proportioned in relation to
that of the shot that until the moment at which the shot quits the barrel the breech
bolt only recoils a short distance, no escape of gases will occur because the slower
moving breech bolt, together with the cartridge case, will be ample to maintain a
gas tight closure of the breech. The further recoil of the bolt is utilized to
compress an elastic cushion such as a spring whereby to return the bolt to the closed
position of the breech after the bolt has reached its rearmost position after a new
cartridge has been inserted or passed from the magazine into the breech, whereupon
the weapon is again ready for firing.
I am aware that the wilization of the recoil for opening the breech and extracting the
spent cartridge case forms the subject of Letters Patent granted to Hiram Stevens Maxim,
respectively dated Jun 26. 1883 No. 3178 July 16. 1883 No. 3493 May 23. 1884
No. 9407 May 26. 1884 No. 8242 but my improved fire-arm is distinguished from
those described in the aforesaid Patents by its greater simplicity as will hereinafter
appear.
Reference is to be had to the accompanying drawings, forming part of this
Specification, wherein
Figures 1 and 2 shew the new breech closing system in two positions.
Figure 3 shews the breech bolt in perspective and end view.
The position of the bolt shewn in Figure 1 is that occupied at or before the
moment of firing, whilst that shewn in Figure 2 is that occupied at the instant

page_text: immediately after the discharge, when the projectile has already quitted the barrel
and the breech bolt has recoiled.
A is the case in which the breech closing bolt B can slide longitudinally within
certain limits. The pressure of the spiral spring C on the rear end of the bolt B
tends to force it forwards into the closing position, Figure 1, but the arrangement
of the spring C may be varied and its action on the bolt B may be effected
through a rod or other intermediate member. The bolt is provided near.
its front end with a stop formed by a cross-pin B driven into a slot b
and which on the recoil of the bolt strikes the end a of the slot in the breech
casing A with its projecting ends whereby the recoil of the bolt is limited. The
empty cartridge case D thrown back along with the bolt by the force of the
explosion strikes the ejector al whereby it is ejected in the usual way.
The firing and loading mechanism are omitted from the drawing but the operation
will be readily understood. The tension of the powder gases reacts in a forward
direction upon the projectile and rearwards through the base of the cartridge case
upon the heavier breech closing bolt to whose inertia is added the resistance of the
spring C and the firing mechanism. The resistance opposed to the gas pressure is
therefore considerably less in the forward than in the rearward direction. Hence
the recoil of bolt B is so slow that the projectile leaves the barrel E before either
the cartridge case, which fits tightly in its chamber F, or the bolt can recoil far
enough to permit any rearward escape of the gases. On the recoil of the bolt the
empty cartridge case is ejected and the firing mechanism is again cocked. By the
forward motion of the bolt effected by the spring C a fresh cartridge is pushed into
the barrel and the bolt returned to the closed position whereupon the arm is again
ready for firing.
This new system is distinguished from known systems such as those of Maxim
hereinbefore referred to by its extreme simplicity which is of great importance for
military weapons this greater simplicity being due to the fact that no extractor is
required to withdraw the spent cartridge case from the breech. Moreover, greater
accuracy of fire is obtained by reason of the reduction of the recoil of the weapon
to a minimum.
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
A breech bolt system for fire arms wherein the breech bolt, instead of being
locked in the closed position before and at the moment of discharge, is free to recoil
but is made of such dimensions as to oppose sufficient inertia to the rearward pressure
of the gases as to ensure such a slow recoil motion of the bolt that the projectile will
have quitted the barrel before an escape of the gases at the breech is possible and
wherein the complete recoil of the bolt under the gas pressure ejeets permits the
empty cartridge case to be ejected without the use of an extructor and recocks the firing
mechanism, substantially as specified.
Dated December 30th 1802
T. BERGMANN,
By A. M. & Wm. Clark,
53, Chancery Lane, London, Chartered Patent Agents.