US2464409A - Gas-operated firearm - Google Patents

Description

- March 1949- H. F. Mos sBERe GAS OPERATED 'IFIREARM Filed Aug. 25, 1943 ATTORNEY INVENTOR Harold I-I'Mossfierg.

M miiwm mw Patented Mar. 15, 1949 GAS-OPERATED FIREARM Application August 25, 1943, Serial No. 500,184

Claims.

This invention relates to improvements in gasoperated firearms of the small arm type and more particularly to mechanism retracting means whereby the firearm may be classed as gas-operated.

The so-called gas-operated class of firearms obtain the energy for retracting a loading and/or firing mechanism, such as a bolt, to dispose it and cooperating parts in cartridge firing position, the gas pressure required being obtained from the barrel during the period the projectile is propelled therethrough. In some instances the recoil action obtained at the moment the cartridgeis fired is utilized for retracting the firing mechanism and in others both the gas pressure and the recoil action is used.

One object of the present invention is to provide means whereby a firearm is adapted to use both gas pressure and/or the recoil action in a novel manner whereby the firing mechanism of the firearm will be automaticall replaced into an initial position when a cartridge is fired.

Another object is to provide means in a firearm whereby the maximum gas pressure developed in the barrel upon firing a cartridge will be utilized to retract the loading and firing mechanism of the firearm.

Still another object of that invention is to provide gas-operated means in a firearm of the above nature, which will cause the gas pressure developed in the barrel to be imposed directly upon one of the principal parts of the loading and firing mechanism thereof.

A further object is to provide an improved form of gas-operated firearm which will be relatively inexpensive to manufacture, simple in construction, of few parts, and which is very efilcient and durable in use.

With these and other objects in View, which will appear as the description proceeds, there has been illustrated in the accompanying drawings one form in which the invention may be embodied in practice.

In the drawings, wherein like reference numerals designate like parts throughout the several views:

Figure 1 is a side elevational view of a small calibre firearm embodying the features and principles of this invention;

Figure 2 is a longitudinal sectional view through the receiver and breech end of the barrel of the firearm shown in Figure 1;

Figure 3' is a sectional view similar to Figure 2 but'with the loading and firing mechanism of the firearm shown in retracted position;

Figure 4 is a cross-sectional View taken on the line 4-4 of Figure 2;

Figure 5 is a broken sectional View taken on the line 5-5 of Figure 4; and

Figure 6 is a broken sectional view taken on the line 6-6 of Figure 4.

Referring to the drawings, and particularly to Figure 1, the firearm selected to illustrate the improved features and principles of this invention, is similar to that fully shown and described in my pending application Serial No. 327,591, filed April 3, 1940, now Patent 2,339,027, issued January 11, 1944. The firearm generally comprises a combined stock and forearm I 0, II respectively, a trigger guard l2, and a barrel l3, which is removably secured into the forward end of a receiver I4, and, with it, is removably secured to the forearm H by a take down screw [5, which screw 15 is screw-threaded into a post I6 extending downward from the receiver M. Suitable rear and front sights I! and 18 respectively are also provided.

As described in the above referred to application, the receiver I4 is provided with a slot I9 to allow the ejection of empty cartridge cases, and the barrel I3 is provided with the usual cartridge receiving chamber 2| formed in its rear, or breech, end 22, to receive a cartridge 23 fed, or inserted into the receiver as in this instance, through an opening 24 provided in the upper surface of the receiver M.

The cartridge 23, when inserted into the receiver I4, is adapted to be engaged and firmly seated in said chamber 2|, and fired While therein, by a bolt 25 which is slidably mounted in the receiver I4. The forward end of the bolt 25 is counterbored, as at 26, to receive the head 21 of the cartridge 23, and has a primer striking lug 28 protruding therefrom in position to strike the cartridge primer and thus fire the cartridge. A cartridge case extracting and ejecting spring finger 29 is secured to the bolt 25 by a screw 3| and extends forwardly along the bolt, in a groove 32 provided therefor, into position to dispose a hook end 33 thereof under the cartridge head 21, when the bolt 25 is slid into it forward position, and thereby adapt it to draw the cartridge case from the chamber 2| when the bolt 25 is retracted. The arrangement is such that after the cartridge case has been fully withdrawn from the chamber 22 it will be thrown downwardly and out of the opening H! by the finger 29 acting, through the hook end 33, upon the cartridge case head.

The bolt 25 is constantly under the tension of a driving spring 34 which is disposed in a bore 35, provided in the bolt, and reacts between the bolt and a rear end plug 36 secured in the rear end of the receiver M to drive the bolt 25 forwardly to position its forward face into close proximity to the rear face of the breech end of the barrel. A thumb enga-geable knurled member 31 extends outwardly from the bolt 25 through an elongated opening 38 (Fig. 1) formed in the side of the receiver M, whereby the bolt 25 may be retracted by hand against the tension of the spring 34 and be guided in its to and fro movements in axial alignment with the barrel I3. In this instance the bolt is adapted to be releasably held in its retracting position and against th action of the spring 34, by the cooperation between a shoulder 39 provided on the undersurface of the bolt 25 and a hooked end 40 provided on an arm 4| formed on a trigger 42 which is pivoted to the receiver I4 by a pin 43. slight pull on a finger piece M of the trigger 42 against the action of a trigger spring 55 will disengage the hooked end 45 from the shoulder 39 on the bolt 25 to permit the spring 36 to act to drive the bolt 25 forwardly and thereby fire a cartridge 23 disposed in the chamber 2 While in the above referred to application the recoil action caused by firing a cartridge was entirely relied upon to retract the bolt 25, means is provided herein for utilizing the gas pressure developed in the barrel l3 when a cartridge 23 is fired. In contradistinction to many of the well known forms of gas-operated firearms, the bolt 25, or firearm loading and firing means, is retracted by means of this invention substantially simultaneously with the firing of the cartridge and not after the cartridge ball, or bullet, has traversed the greater part of the length of the barrel. By the use of the herein disclosed means gas pressure acts directly upon the bolt 25 to retract it as the bullet leaves the cartridge case, thus effecting a more speedy action in the operation of the firearm. By causing the gas pressure to act directly upon the bolt 25, as is illustrated herein, no lost motion is experienced as would be if connections were made through the usually provided various levers and sliding parts.

The above referred to means to utilize the gas pressure as soon as developed in the barrel by the firing of a cartridge 23 comprises, in its simplest form, a duct leading from the rear end face of the breech end 22 of the barrel E3 to a position directly forward of the front end, or case shoulder, 52 of the chamber 2|. The duct 5| is connected, at this point, to the bore 53 in the barrel l3 by a cross duct 54. By means of the ducts 5| and 54 gas pressure developed in the barrel as soon as the cartridge 23 is fired acts upon the loading and/or firing mechanism to retract it. In the form illustrated this action is upon a portion of the forward face of said bolt 25, said face being constituted herein by the end face of a stud 55 extending from the bolt 25 and into the duct 5|. As illustrated, the stud 55 acts within the duct 5| similarly to the action of a piston within a cylinder.

To facilitate manufacture, the breech end of the barrel H5 is extended rearwardly in the form of a lip, or tongue, 56 to overlie a horizontal surface 51 formed on the bolt 25 by cutting away part of the forward end of the bolt. The cutting away of part of the bolt 25 to provide the surface 51 forms a forwardly directed shoulder 58.

The duct 5| is extended rearwardly through the extended lip 56 in alignment with the stud The arrangement is such that a 4 55 which extends forwardly from the face of the shoulder 58, and is adapted to enter the open end of the duct 5|.

The operation of the above described firearm is briefly as follows. A cartridge 23 is inserted into the receiver I4 and into the chamber 2|, the bolt beingheld in its retracted position by the hooked. end engaging the shoulder 39 on the bolt. The trigger 42 is actuated to release this engagement and the bolt 25 is driven forward by the spring 34 to enter and seat the cartridge 23 in the chamber 2| and to simultaneously fire the primer. When the cartridge is fired, gas pressure acting through the ducts 5|, 54 retracts the bolt 25 whereupon the empty cartridge case is ejected. As in the form illustrated recoil action will also be experienced, a particularly fast retraction of the bolt will take place and should any of the well known types of cartridge feeding means be employed in combination with the features of this invention, a particularly fast automatic firearm will be obtained.

While there has been shown and described herein, one form of an improved firearm, it is to be understood that the invention may be embodied in other forms without departing from the spirit or essential attributes thereof. It is, therefore, desired that the present embodiment be considered in all respects as illustrative and not restrictive, reference being had to the claims rather than to the foregoing description to in dicate the scope of the invention.

Having thus fully described the invention, what is claimed as new and for which it is desired to secure Letters Patent is:

1. In a firearm, a receiver, a barrel having a bore, a bolt movable in said receiver to present its forward end face into close proximity with the breech end face of the barrel, said barrel having a rearwardly directed tongue extending from its breech end face, said bolt being cut away to receive said tongue and to form a forwardly directed shoulder, the barrel having a duct leading from its bore to the rear end face of said tongue, and a stud extending from the forwardly directed shoulder of said bolt and adapted to enter and to close the rear open end of said duct when the forward end face of the bolt is in close proximity with the breech end face of the barrel.

2. In a firearm, a receiver, a barrel extending from the front end of the receiver and having a first bore therethrough and a cartridge receiving chamber formed in its breech end, a bolt slidable in said receiver in axial alignment with said barrel, means to guide said bolt in its axial movements, means to move said bolt forwardly to force a cartridge into the cartridge chamber in said barrel, said bolt being cut away at its forward end to provide a forwardly directed shoulder, a tongue extending rearwardly from the breech end of said barrel and overlapping the cut away portion of said bolt, a second bore in said barrel leading from the rear end of said tongue and formed in the barrel wall between the said cartridge chamber and the outer periphery of the barrel-to form a cylinder, a duct formed in the barrel leading from the front end of the second bore to the first bore at a point forward of the cartridge chamber in said barrel to direct exploded gases to the said second bore, and a stud, forming a piston, extending from the forwardly directed shoulder on said bolt in alignment with the second bore in said barrel to enter the same when the bolt is moved into position to insert a cartridge into the cartridge chamber and adapted to be expelled therefrom by pressure of the gases formed, due to the explosion of said cartridge, and force the bolt rearwardly away from the breech end of said barrel.

3. In a firearm, a receiver, a barrel having a bore and extending from said receiver, and a bolt movable on said receiver to present its forward end face into close proximity with the breech end face of the barrel, said bolt having a lengthwise opening extending rearwardly from its forward end face to form a forwardly facing shoulder, said barrel having a portion extending rearwardly from its breech end face and adapted to be received in the opening in said bolt, said barrel having a duct leading from its bore through the rearwardly extending portion to the rear end face thereof.

4. In a gas-operated firearm, a receiver, a barrel having a bore, a bolt movable in said receiver to present its forward end face into close 6 end face of said tongue with its open end facing said shoulder in said bolt.

5. In a firearm in accordance with claim 3 and having a stud extending forwardly from the forwardly facing shoulder, formed by the opening in said bolt, and adapted to enter the duct in said barrel when the adjacent bolt and barrel end faces are in close proximity.

HAROLD F. MOSSBERG.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 319,595 Maxim June 9, 1885 729,413 Reifgraber May 26, 1903 1,020,596 Brauning Mar. 19, 1912 FOREIGN PATENTS Number Country Date 22,098 Austria Nov. 10, 1905 45,225 Austria Dec. 10, 1910 453,658 Germany Dec. 15, 1927 593,045 Germany Feb. 20, 1934

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