US3000126A

US3000126A - Cartridge-guiding mechanism

Info

Publication number: US3000126A
Application number: US335111A
Authority: US
Inventors: Russell S Robinson
Original assignee: Individual
Current assignee: Individual
Priority date: 1953-02-04
Filing date: 1953-02-04
Publication date: 1961-09-19
Anticipated expiration: 1978-09-19

Description

Sept. 19, 1961 R. s. ROBINSON CARTRIDGE-GUIDING MECHANISM 3 Sheets-Sheet 1 Filed Feb. 4, 195

INVENTOR ATTORNEY5 Sept- 1961 R. s. ROBINSON 26 CARTRIDGE-GUIDING MECHANISM Filed Feb. 4, 1953 3 Sheets-Sheet 2 Z 60 7o 69 G5 4 a 7: 5a

Z 49 5 42 54 9 54 55 I 43 as E is; Q3

5? ill 4 H 44 45 INVENTOR 4 4 6 f 45 c2 fi E ;gg W

ATTORNEYS p 1961 R. s. ROBINSON 3,000,126

CARTRIDGE-GUIDING MECHANISM Filed Feb. 4, 1953 3 Sheets-Sheet 3 BY W I W ATTORNEYS This invention relates to improved means for controlling and guiding cartridges and cartridge cases while they are within the barrel extension or receiver of a firearm and during such operations as ramming the cartridges into the chamber, extraction from an ammunition belt or chamber, and ejection of the cartridge cases after firing.

In many known types of repeating or automatic firearms the cartridge is ejected forwardly from the receiver after being withdrawn from the chamber or is extracted rearwardly from an ammunition belt by which the cartridges are supplied to the gun. In such cases the ejection of the cartridge takes places at a different level from that of the chamber or barrel axis or it is extracted from the ammunition belt at a level different from that of the chamber, and it is, therefore, necessary to provide for handling and guiding of the cartridges, in a direction transverse to the axis of the barrel, from the magazine or belt to the level of the barrel axis or from the latter to the level at which they are ejected. This handling of the cartridges is sometimes performed by moving parts such as transporters or displacers, the function of which is to displace the cartridge from one level to another, and this usually occurs during a part or all of the rearward movement of the breech bolt.

It is contemplated by the present invention to perform the transverse displacement or handling of successive cartridges or cartridge cases during recoil stages of the mechanism without the use of such moving parts, the displacement and guiding of the cartridges being effected by permanent guides being built into the interior of the barrel extension or receiver.

It may be assumed for purposes of description that during the successive processes of removing cartridges from the ammunition belt or magazine to the chamber and thence from the chamber through the ejection passage, the cartridge is displaced in a vertical plane so that the cartridge must be moved from one plane to another to be fed into the chamber and again to a third plane when ejected. To effect the displacement of the cartridges, I employ a breech bolt, the body of which is somewhat narrower than the maximum diameter of the cartridge case, the bolt being provided with the usual extractors and adapted to reciprocate in a vertically arranged slot within the barrel extension or receiver, which slot is also narrower than the maximum diameter of the cartridge case. To accommodate the cartridges within the barrel extension or receiver, sloping grooves are constructed in one or both of the inner walls thereof, and these slots provide clearance or passages for longitudinal movements of the cartridge but control its vertical movements and thus serve as paths for the cartridge during its reciprocation, each cartridge being pulled rearwardly by an extractor or extractors, but pushed forwardly by the action of the breech bolt, the grooves guiding the cartridge so as to cause it to move from one level to another during such reciprocations.

In the forms of my invention wherein the cartridge is extracted rearwardly from the belt or chamber and then moved forwardly for ejection or to be rammed into the chamber, the rearward guiding groove merges into a forward guiding groove and clearances are provided in the walls on the barrel extension so that as the cartridge continues to move rearwardly past the merge point, the relative angle between the ribs or grooves forces a change in States Patent NiC the direction of the cartridge, or cartridge case, whichever it may be, substantially toward the next movement and along the forward guiding groove. The cartridge is swung or rotated to its new position or attitude, and the forward portion of the cartridge case may pass over a pawl or detent which will prevent it from returning into the original groove.

In constructions for providing for vertical ejection, the rear end of the upper surface of the rearward guide ribs displaces the extracted case away from the feedway and terminates in a buttress or separate ejector which performs the ejection as soon as the rearwardly extracted cartridge reaches the ejection station.

To prevent the cartridge case from returning into the feedway after being withdrawn from the chamber, a buttress is incorporated in the belt which protrudes forward of the bolt face and prevents the case from rising into the feedway until it is engaged by the displacing ribs. This buttress may comprise the inner side of an outwardly spring-pressed feed pawl pivoted to the breech bolt for loading and ramming purposes or it may comprise a similar but'inwardly spring-pressed pawl with an inner beveled face to give the rearward moving cartridge case an initial lateral movement, in the direct-ion of the next displacement, during rearward movement of the breech bolt while the cartridge is being withdrawn from the firing chamber.

One object of the present invention is to provide new and improved means for handling and guiding cartridges and cartridge cases through various stages of feeding the cartridges to the chamber and extracting them from-the chamber, and ejecting them from the receiver or barrel extension.

A still further object of the invention is to provide a firearm wherein the functions of loading, extracting and ejecting a cartridge in an automatic firearm is effected without the use of moving parts to displace the cartridge from one level or position to another transversely of the axis of the cartridge.

Still another object of the invention is to provide for the guiding of the cartridge during the loading and extraction thereof by means of grooves provided upon the inner wall of the barrel extension or receiver, these grooves being so formed that as the cartridge is moved longitudinally therein, it will be displaced transversely from one level or position to another in order that a return longitudinal movement of the cartridge will place it at another level either for insertion into the chamber or for ejection from the firearm.

To these and other ends the invention consists in the novel features and combinations of parts to be hereinafter described and claimed.

In the accompanying drawings:

FIG. 1 is a somewhat diagrammatic sectional view of the chamber and reeciver or barrel extension of an automatic firearm embodying my invention;

FIG. 2 is a similar view showing the parts in different positions;

FIG. 3 is a view similar to FIG. 1 showing the parts in still another position;

FIG. 4 is a transverse sectional view on line 4--4 FIG. 1;

FIG. 5 is a transverse sectional view on line 55 of FIG. 1;

FIG. 6 is a longitudinal sectional viewthrough the center of the chamber and receiver or barrel extension of a firearm showing another form ofmy invention;

FIG. 7 is a view similar to FIG. 1 but showing the breech bolt in its rearward position;

FIG. 8 is a sectional view on line 8-8 of FIG. 7;

FIG. 9 is a sectional view on line 9--9 of FIG. 7;'

FIG. 10 is a sectional View through the chamber and receiver or barrel extension of an automatic firearm showing a third form of my invention;

FIG. 11 is a view similar to FIG. showing the breech bolt in its forward position;

FIG. 12 is a sectional view on line 12-12 of FIG. 10; and

FIG. 13 is a sectional view on line 1313 of FIG. 12.

Referring particularly to FIGS. 1 to 5, there is shown a barrel 10 rigidly secured to a receiver 11. The side walls of the receiver are spaced apart to a sufiicient extent to accommodate between them the breech bolt 12 which it will be understood reciprocates within the receiver, the bolt being moved rearwardly by the explosion of the cartridge in the chamber 13 of the barrel and returned forwardly by any suitable means, such as the spring shown diagrammatically at 14.

The wall 15 of the receiver is provided with relatively shallow grooves 16 within which the bolt is guided by means of the ribs 17 so that the bolt travels rearwardly in a straight path parallel with the axis of the barrel.

The opposite or left wall 18 of the receiver is spaced sufliciently far from the wall 15 to slidably accommodate therebetween the body of the breech bolt but is not spaced sufliciently far to provide clearance for the cartridge case except at the neck thereof. However, this wall 18 is provided with recessed but inwardly facing grooves of sufficient depth that clearance will be provided for the maximum diameter of a cartridge case. That is, the base of these grooves is the same distance from the center line of the gun as the inner face of the wall 15, as will be more fully described hereinafter.

The magazine is shown at 19 which is removably secured to the receiver and communicates at its upper end with an opening 20 in the lower part of the receiver adjacent the chamber in the barrel, and cartridges A, B, C, and D are illustrated, the cartridge A being shown as being ejected from the gun, the cartridge B lying in the chamber, the cartridge C being the upper one in the magazine which will be next fed into the chamber, while the cartridge D lies below cartridge C (FIG. 1).

The breech bolt 12, which reciprocates between the

receiver walls

15 and 18, carries an extractor 21 of usual form, this extractor lying between the ribs 17 so that it is accommodated in a relieved portion 22 of the wall 15 between the grooves 16. Adjacent its forward end this portion of the Wall 15 is further relieved, as shown at 23 in FIG. 4, to permit the outward displacement of the extractor 21 as it engages the rim of cartridge B during its final ramming into the chamber. The bolt is also provided with a ramming lug or buttress 24- which, when the breech bolt is in its forward position, lies below the rim of a cartridge in the chamber and prevents the cartridge dropping downwardly with respect to the breech bolt when it is being extracted. The bolt is further provided with an upwardly projecting finger 25 which lies above the face of the bolt at a rearward angle and which, as will be later explained, completes the forward ejection of the cartridge cases.

The wall 18 of the receiver or barrel extension is grooved as previously noted, these grooves being three in number and comprising a groove 26 which is disposed so as to provide clearance for a cartridge being rammed from the magazine 19 into the firing chamber, a groove 27 which is so disposed that its lower edge 27 acts to displace the rear end of the cartridge in an upward direction during a part of the recoil movement of the bolt, and a groove 28 through which the cartridge or cartridge shell, as the case may be, is ejected in a forward direction. It will be noted that the groove 27 provides communication between the groove 26 and the groove 28.

The acute angle between the

grooves

27 and 28 is relieved forwardly of the corner 29 to the same depth as the grooves for a forward distance slightly in excess of the distance between the rim and shoulder of a cartridge, the forward limit of this relieved portion of the junction of these grooves being defined by the edge 30 so that this portion of the cartridge (which is too large to be received between the walls 15 and 18) may be permitted to swing upwardly and pass from one groove to the other. This permits the rotation of the cartridge from the groove 27 to the groove 28. When the rim is moved upwardly past corner 29, the forward or reduced end portion of the cartridge case in front of the shoulder is sufiiciently small to pass through the space between the walls of the receiver.

In this relieved area of the wall 18 a detent member 32 may be slidably mounted in the receiver wall and urged inwardly by spring 33. This detent will be urged outwardly when the cartridge is swung upwardly from the groove 27 into the groove 28 and then will be moved inwardly below the cartridge or cartridge case so as to prevent the return of the latter into the groove 27. The bolt may be provided with a firing pin 34, which firing pin may be actuated by a hammer 35 pivoted to the bolt and provided with an upwardly projecting finger 36 which engages a lug 37 on the receiver when the bolt is in its battery position.

The operation of the structure of this form of my invention is such that as the bolt moves forward from the position shown in FIG. 2, the buttress 24 engages the rim of cartridge B and thrusts it forward from the magazine 19 into the firing chamber 13 of the barrel by way of groove 26, this groove, it will be understood, being sufliciently deep to accommodate the maximum diameter of the cartridge case. At the same time the finger 25 thrusts cartridge A forwardly out of the ejection groove 28, the forward position of the bolt being shown in FIG. 1, where it will be noted cartridge B lies in the firing chamber while cartridge A has been ejected from the receiver.

As shown in FIG. 1, the extractor is in engagement with the rim or cannelure of the cartridge when the bolt is in battery position. As the bolt moves rearwardly from this position carrying cartridge B or the empty case thereof, the buttress member 24 prevents any downward movement of the rear end of the cartridge until the lower edge 27 of the groove 27 meets the rim of the cartridge and causes it to move upwardly until it reaches the corner 29 which is a lower edge of groove 28. This position of the cartridge is shown at B in FIG. 3. At this point the cartridge continues to move rearwardly a short distance until the upper edge of the goove 27 contacts the upper portion of the rim of the cartridge and causes the latter (upon continued rearward movement) to rotate or swing upward past the pawl or detent 32 into alignment with the groove 28. In this movement the cartridge case swings substantially about its rear portion, the larger portion of the cartridge swinging upwardly between the corner 29 and the shoulder or edge 30. The cartridge is now in the position shown at A in FIG. 2, and the forward end is prevented from dropping downwardly again into the groove 27 by the detent 32.

The bolt has now reached its most rearward position and is now ready to begin its forward movement. During this forward movement, as has been explained, the finger 25 contacts the cartridge case A and ejects it forwardly while cartridge B is being thrust into the chamber.

In the form of my invention shown in FIGS. 6 to 9 of the drawing, I have illustrated a gun casing 40 incorporating a belt feedway 41 into which belted cartridges 42 are fed by any of the usual feeding means. These cartridges are designed to be rearwardly extracted from the belt for forward ramming into the chamber and again rearwardly extracted from the chamber for forward ejection from the casing or receiver, as shown for example in dotted lines at 42 in FIG. 6. A barrel 43 is threadedly fixed to the gun casing, and a breech bolt 44 is slidably mounted therein. The breech bolt is provided on each side wall thereof with a rib 45 which ribs slide in opposing grooves 46 at the inner surfaces of the walls of the casing 40, which inner surfaces, as shown in FIG. 8, are substantially parallel.

At the front ends of the ribs 45 a pair of inwardly spring-pressed extractors 47 are carried by the bolt 44, the extractors being adapted to engage diametrically over the rim of a cartridge case. :The body of the breech bolt is of substantially the same width as the diameter of the mouth of the cartridge case 42, which is, of course, considerably smaller than the maximum diameter of the cartridge, and the vertical slot 48 or space between the inner surfaces of the walls of the gun casing is of substantially the same diameter so as to provide clearance for the body of the breech bolt and the mouth of the cartridge case but not for the body of the latter.

A riser 49 extends upwardly over the breech bolt 44, which riser is of substantially the same width as the body of the bolt. The front face 50 of the riser 49 is displaced further forward than the plane of the front face of the breech bolt and is separated therefrom by the horizontal step 51. At the top of the riser is a buttress 52 which extends forward a short distance. The under side of the buttress 52 makes substantial clearance over the top of the rim of a cartridge in the feedway 41, and likewise the step 51 makes substantial clearance over the top of a rim of the cartridge in the chamber 43 of barrel 43 so as to give the cartridges some freedom of movement in a vertical direction with respect to these portions of the bolt when the latter is withdrawn rearwardly. The riser 49 also carries a pair of shallow extractors 53 (one on each side face) which slide in grooves 54 in the gun casing 40. These grooves are also provided in the inner'faces of the opposing walls of the gun casing and are parallel to the grooves 46.

To accommodate the cartridges within the relatively narrow space 48 between the walls of the gun casing, symmetrical guide grooves are cut in the opposing faces of these walls by drilling holes slightly larger in diameter than the maximum cartridge diameter, the holes being drilled before the slot 48 is cut. These grooves comprise a downwardly and rearw ardly inclined belt extraction groove 55, a downwardly and forwardly inclined ramming groove 56 which intersects the belt extraction groove and is the groove through Which the cartridge enters the chamber. They also comprise a downwardly and rearwardly inclined chamber extracting groove 57 and a downwardly and forwardly inclined ejection groove 58. As will be noted from the drawing, the

grooves

55 and 56 intersect each other at their rear ends and make substantially equal angles with a horizontal plane through their point of intersection. Likewise the

grooves

57 and 58 intersect at their rear ends and make substantially equal angles with the horizontal plane passing through their intersection.

A relief area at 59 is provided upon each side wall of the gun casing between the

grooves

55 and 56 and similar relief or depressed areas 60 are provided upon each side wall of the casing between the

grooves

57 and 58. As shown in FIG. 9, these relief areas are cut as deeply as the grooves themselves so as to allow passage of the full diameter of the cartridge at these areas from one groove to the next.

Also, as shown in FIG. 9,

non-return pawls

61 and 62 are provided in each of these relieved areas, these pawls being slidably mounted in the walls of the gun casing. The pawls 61 are urged inwardly by springs 63, while the pawls 62 are urged inwardly by springs 64. =Pawls 61 will prevent the return of the cartridge into groove 55 after it has been turned or swung into groove 56, and in a similar manner pawls 62 prevent the return of the cartridge cases into grooves 57 after they have been swung or turned into grooves 58.

At the under side of the breech' bolt 44 is a centrally disposed downwardly extending finger or lug 65 which is adapted to engage a cartridge in the groove 58 and impel it through this groove and out of the ejector port 66 of the casing, as shown at 42 inFIG. 6. It is understood that the breech bolt is returned by anyof the well-known means, such as the usual spring (not shown). The firing of the cartridge in the chamber may be effected in any convenient way, such, for example, as providing a firing pin 67 which is slidably mounted in the breech bolt 44, which pin is actuated in a forward direction by a hammer 68 pivoted at 69 to the lug 65, the lower end or tail 70 of the hammer being adapted to engage a portion 71 of the casing upon the movement of the bolt to battery position so as to project the firing pin forwardly and discharge the cartridge in the chamber. The lower portion of the front face of the breech bolt and of the lug 65 is cut back slightly in order to afford clearance for the cartridge to rock or swing downwardly when so constrained by the walls of the guiding grooves.

The operation of the device may now be briefly described. With a cartridge 42 having been fed into the central position in the feedway 41, as shown in FIG. 6, as the breech bolt moves real-wardly from the forward position shown in the figure along the downwardly sloping grooves 46, the belt extractors 53, which are seated in the sides of the riser 49 of the breech bolt,"

draw the fed cartridge 42 from the belt and feedway, the underside of the buttress 52 preventing it from rising and therefore disengaging itself from the extractors as. it moves rearwardly and as the bolt moves rearwardly and downwardly in an inclined path. As the cartridge is moved rearwardly it is contacted by the upper edges or lips of the groove 55 whereupon it is displaced downwardly along the groove 55 until it meets the rear end of groove 56. As the latter groove is inclined upwardly in a rearward direction, the rear end of the cartridge is swung upwardly slightly, thus rocking the cartridge into alignment with the groove 56. In being rocked or swung from one groove to the other, the body of the cartridge has been moved from the upper side to the lower side of the non-return pawls 61 so that it cannot return to the groove 55.

As the breech bolt 44 then moves forwardly, the cartridge 42 is thereby ram-med through the groove 56 into the firing chamber of the barrel 33 where the extractions 47 engage the cartridge rim. When the breech bolt 44 moves rearwardly after the discharge of the gun, the cartridge case is withdrawn from the chamber and the stop or shoulder 51 prevents it from rising and becoming disengaged from the extractors 47 until it is contacted by the upper edges or lips of the groove 57. The rear end of the cartridge is then displaced downwardly, and as it moves rearwardly in groove57, it meets the groove 58 and, as before, is rocked into substantial alignment with groove 58, past the pawls 62, and is latched in position in this groove by these pawls, as previously explained in connection with the pawls 61.

The subsequent forward movement ofthe breech bolt 44 results in the ramming of the cartridge case 42 forward through the ejection groove 57 and out of the ejection port 66, as shown in FIG. 6. At the same time it will be understood that a fresh cartridge has been extracted from the belt and moved into the firing chamber, as previously described. I

In the form of my invention shown in FIGS. 10 to 13 of the drawings, the firearm is of the type in which the barrel recoils and the movement of the breech bolt is interlinked to that of the barrel. The device comprises a recoiling barrel to which is fixed a barrel extension 81, the barrel sliding within fixed guides (not shown) in the casing 82 from the position shown in FIG. 11 to that shown in FIG. 10. The casing 82 incorporates a magazine feed system 82 of known construction which brings

successive cartridges

83 and 83 into the position shown by the cartridge 83 from which the cartridge is fed into the chamber, as will be later described. The casing is also provided with an ejection port 84 at itsi 7 underside to permit the exit of the ejected cartridge cases. At the breech end of the barrel is the usual firing chamber 84 and a spring 84' provided in the magazine urges the cartridges downwardly into feeding position.

Slidably mounted in the barrel extension 81 is a breech bolt 85 which incorporates oppositely disposed ribs 86 slidably supported in sloping grooves 87 constructed within a boltway slot designated generally by the numeral 88 in the barrel extension 81. Pivoted to the breech bolt at 89 is an extractor 89* which is urged inwardly by the spring 89 which is designed to engage the underside of the rim of a cartridge case in the chamber 84 Also pivoted to the breech bolt at 90 is a loading pawl 90 this pawl being urged outwardly by a pawl spring 90*. The loading pawl is provided in a recess in the breech bolt so that it disappears into the body of the bolt by engagement with a cartridge in the position of the cartridge 83 shown in FIG. 11 upon recoil of the breech bolt, and rises to the rear of such a cartridge when the breech bolt is in the position shown in FIG. so as to initiate the ramming of the cartridge when the breech bolt moves forwardly.

The underside of the pawl 90 which overhangs the face of the breech bolt 85 makes sufficient clearance over the rim of a cartridge in the firing chamber when the bolt is forward whereby, as the bolt moves rearwardly down its sloping path and the cartridge moves rearwardly along an initial axial path, the pawl does not bind the cartridge along the mouth of the chamber at any point.

The boltway slot 88 of the barrel extension 81 is slightly wider than the maximum diameter of a cartridge case. Toward the rear portion of the slot 88 are opposite internally protruding ledges 91, the lateral distance between which is narrower than the diameter of the cartridge case rearwardly of its shoulder. The upper surfaces 92 of these ledges 91 are contoured to make a seat for the fed cartridge 83 (FIG. 10*) so as to align the cartridge correctly for ramming or loading into the firing chamber. The undersurfaces 93 of the ledges 91 are sloped to displace the rim of a cartridge, being extracted from the chamber, away from the barrel axis.

Mounted upon the walls of the slot in the barrel extension at the undersurface 93 of the ledges 91 at a point in front of the rearward position of the bolt 85 are ejector buttresses 94. These buttresses are inserts mounted in recesses in the ledges 91 and are urged forwardly by springs 95. It will be understood that the upper portion of the breech bolt above the ribs 86 is sufiiciently narrow so as to slide freely between the ledges 91.

The bolt may be interlinked with the barrel extension by any of the usual means so as to be carried rearwardly upon the recoil of the barrel. As shown, a detent lever 96 is pivoted to the barrel extension at 97, this lever being provided with a nose 98 adapted to engage in a recess 99 of the bolt. The casing is provided with the cam surfaces 101 and 102 to engage the detent so that its nose will be moved into and out of the recess 99. When the tail 100 engages the sloping cam surface 102 on the casing, the nose 98 of the detent 96 will be moved downwardly, thus freeing the bolt from the barrel extension and permitting the bolt to move rearwardly independently of the barrel extension. The bolt may be returned to battery position by any suitable means such as the spring 103, and upon its return when the nose 98 of the detent strikes the sloping surface 101 of the casing, it will be cammed upwardly into engagement with the recess 99 of the bolt and again link the latter to the barrel extension.

The firing of a cartridge in the chamber may be efi'ected by any desired means, such, for example, as firing pin 104 spring pressed rearwardly by a spring 105, the rear end of the pin being adapted to be engaged by a lever 106 pivoted to the bolt at 107, the tail of the lever being adapted to engage a lug 108 provided on the casing when the bolt reaches battery position.

The operation of this embodiment of my invention is such that with the breech bolt in its rearward position and with the cartridge 83 held downwardly by the spring 84 as shown in FIG. 10, upon the upper surfaces 92 of the ledges 91 of the barrel extension, the breech bolt, as it moves forward with respect to the barrel extension, will engage the cartridge 83 by means of the loading pawl and thrust the cartridge 83 into the chamber, as shown in FIG. 11. In this position the cartridge rim will be engaged by the extractor 89 and the cartridge 83 next above the cartridge 83 in the magazine will be sup ported upon the top of the bolt 85 until the bolt returns to its rearward position.

With the parts in the position shown in FIG. 11 the

barrel assembly

80 and 81 will recoil upon the discharge of the cartridge, and the breech bolt will move rearwardly down its sloping path with respect to the barrel extension 81, it being understood that the barrel extension will move only to the position shown in FIG. 10, while the breech bolt will move the greater distance to the position shown in this figure. During the rearward movement of the breech bolt, the spent case of the cartridge 83 which is engaged by the extractor 89 will be extracted from the firing chamber and moved rearwardly, first in an axial direction controlled by its close fit within the chamber, and then by the action of the undersurface of loading pawl 90 will be moved down a sloping path until it contacts the undersurface 93 of the ledges 91. These surfaces cause a more rapid displacement of the rim of the cartridge downwardly from the barrel axis whereupon the cartridge 83 can more readily be fed to the ramming position.

As the rim of the spent case continues to be drawn downwardly and rearwardly by the extractor 89*, the ejector faces of the buttresses 94 engage the upper part of the rim and pivot or spin the spent case downwardly around the extractor 89 thereby ejecting it from the gun casing through the ejector port 84, as shown in dotted lines at 83. The breech bolt continues its rearward movement until it reaches its full rearward position, shown in FIG. 10, by which time the cartridge 83 occupies the position shown for the cartridge 83 in FIG. 10, where it rests upon the upper surface 92 of the ledges 91 ready for ramming into the firing chamber upon the next advance of the breech bolt.

It will be understood that the various constructions shown are each readily applicable to firearms having recoiling or non-recoiling barrels as desired. Also, if desired, the latches or detents shown in the first two modifications of my invention may be omitted in some firearms.

While I have shown and described some preferred embodiments of my invention, it will be understood that it is not to be limited to all of the details shown, but is capable of modification and variation within the spirit of the invention and within the scope of the claims.

What I claim is:

1. In a firearm of the repeating type, a barrel having a chamber, a breech extension mounted rigidly therewith, said extension having inner walls spaced apart a distance less than the maximum cartridge diameter, means in said extension providing a groove communicating with the chamber at its forward end and arranged to receive and guide a cartridge for longitudinal movement and to control its vertical movement therein, said groove making an oblique angle with the barrel axis, and said extension also having a cartridge guiding groove making an acute angle with said first groove and intersecting the latter adjacent the mouth of the chamber.

2. A firearm as in claim 1 wherein the axes of said grooves lie substantially in the same plane but diverge in opposite directions from the barrel axis.

3. A firearm as in claim 1 wherein said first groove receives a cartridge and guides it into the chamber.

4. A firearm as in claim 1 wherein a bolt is reciprocably mounted in the casing and provided with extractor means to draw the cartridge rearwardly in one of said grooves and also having means to engage the cartridge and move it forwardly in the other of said grooves.

5. A firearm as in claim 1 wherein said grooves diverge from their intersecting portions, and lands are provided between the divergent portions of said grooves to prevent the passage of the maximum diameter of the cartridge from one groove to the other.

6. In a firearm of the repeating type, a casing, a barrel carried by the casing and provided with a chamber, the walls of said casing being spaced apart less than the bore of the chamber, said walls being provided with a generally longitudinally disposed groove communicating with the chamber to receive a cartridge therefrom, said groove lying at an angle to the chamber axis, means providing a second cartridge-receiving groove in said casing walls, the axis of which is angularly directed relatively to said first groove, and said second groove intersecting the first adjacent its rear end and diverging forwardly therefrom, and a bolt reciprocably mounted between the walls of the casing to engage and move a cartridge through said grooves.

7. In a firearm of the repeating type, a casing, a barrel carried by the casing and provided with a chamber, the Walls of said casing being spaced apart less than the bore of the chamber, said walls being provided with a generally longitudinally disposed groove communicating with the chamber to receive a cartridge therefrom, said groove lying at an angle to the chamber axis, means providing a second cartridge-receiving groove in said casing walls, the axis of which is angularly directed relatively to said first groove, said second groove intersecting the first adjacent its rear end and diverging forwardly therefrom, a bolt reciprocably mounted between the walls of the casing to engage and move a cartridge through said grooves, and means providing a land between the spaced portions of said grooves whereby the passage between the grooves at that point is narrower than the full diameter of a cartridge.

8. A firearm according to claim 6 wherein a land is provided between the divergent parts of said grooves to provide a narrow passage therebetween, and said land terminating at the point of intersection of said grooves to provide unobstructed communication between the grooves and the point of intersection.

9. In a firearm of the repeating type, a casing, a barrel carried by the casing and provided with a chamber, the walls of the casing being spaced apart to receive a bolt therebetween, and said spacing being of less width than the diameter of the chamber, said walls being complementally grooved to provide a cartridge passage leading rearwardly from the chamber and in an inclined direction with respect to the axis of the chamber and also being grooved to provide a second passage intersecting the first at a point spaced rearwardly of the chamber, a land disposed between said passages adjacent the front portions thereof and providing restricted communication between said passages, and said passages communicating with each other adjacent their intersecting portions throughout their full diameters and being of sufficient diameter to permit a cartridge to pass therethrough.

10. A firearm according to claim 9 wherein a bolt is reciprocably mounted between the walls of the casing and provided with means to extract a cartridge from the chamber through said first passage and eject it from the casing through said second passage, said second passage communicating with the exterior of the casing.

11. A firearm according to claim 9 wherein springpressed detents are provided in the walls of the casing at the intersection of said grooves to prevent passage of 10 a cartridge in one direction from one of the grooves to another.

12. In a firearm of the repeating type, a casing, a barrel carried by the casing and provided with a chamber, means in the casing providing intersecting grooves arranged to receive and guide a cartridge for longitudinal sliding movement therein, said grooves being inclined with respeet to the barrel axis, means including a reciprocable bolt for moving a cartridge longitudinally within one of said grooves and swinging said cartridge into the other groove at the intersection thereof, said bolt being provided with a shoulder adjacent one edge projecting forwardly from the front face of the bolt, said bolt also being provided with extracting means, and the inner edge of said shoulder being spaced from a cartridge gripped by said extractors when the bolt is in forward position.

13. In a firearm of the repeating type, a casing, a barrel carried by the casing and provided with a chamber, means in the casing providing intersecting grooves arranged to receive and guide a cartridge for longitudinal sliding movement therein, one of said grooves communicating with the chamber, means including a reciprocable bolt for moving a cartridge longitudinally within one of said grooves and swinging said cartridge into the other groove at the intersection of the grooves, a feed belt carried by said gun, and the other of said grooves leading to a cartridge in said feed belt, and said breech bolt having -a forwardly projecting lug at its front face to overlie and be spaced from a cartridge positioned either in said feed belt or chamber.

14. In a firearm of the repeating type, a casing, a barrel carried by the casing and provided with a chamber, means in the casing providing intersecting grooves arranged to receive and guide a cartridge for longitudinal sliding movement therein, one of said grooves communicating with the chamber, a feed belt, the other of said grooves communicating at its forward end with said feed belt to provide for rearward extraction of a cartridge from the belt, and means including a reciprocable bolt for extracting a cartridge from the belt in a rearward direction in said last-named groove and swinging said cartridge into the other goove and moving it forwardly into the chamber.

15. In a firearm of the repeating type, a barrel having a chamber, a breech extension to which the barrel is rigidly connected and having inner walls spaced apart a distance less than the maximum cartridge diameter, inwardly projecting lands on the extension walls providing intersecting grooves arranged to receive and guide a cartridge for longitudinal sliding movement and to control its vertical movement therein, one of said grooves communicating with the chamber, and means including a reciprocable bolt for moving the cartridge longitudinally within one of said grooves during the recoil of the bolt and swinging said cartridge into the other groove at the intersection of the grooves during the latter part of the recoil.

16. A firearm according to claim 15, in which an additional pair of intersecting grooves are provided, one groove of said last-named pair extending at an oblique angle rearwardly from the mouth of the chamber to permit rearward extraction of the cartridge from the chamber, and said other groove intersecting the first at its end and extending forwardly from the point of intersection at an angle to the barrel axis to permit fonward ejection of the cartridge.

17. A firearm according to claim 1 wherein a breech bolt is provided to engage the rear portion of the cartridge and move it in said grooves, said breech bolt moving between the walls of the casing and being narrower in width than the maximum diameter of the cartridge through at least a part of the depth of the breech bolt.

18. A firearm as in claim 1 wherein inwardly projecting lands are provided on the side walls of the casing to form the grooves between said lands, and wherein a bolt 1 1 is mounted for longitudinal movement in the casing between said lands, -the body of said bolt being narrower than the maximum diameter of the cartridge.

19. A firearm as in claim 15 wherein a spring-pressed extractor means is secured to the bolt to project forwardly therefrom and engage a cartridge, and said means being spaced forwardly of the bolt face to permit rocking of the cartridge as its attitude is altered by said grooves.

20. A firearm as in claim 15 wherein said bolt is provided with an ejecting lug adjacent one edge thereof, and the front face of said ejecting lug being inclined rear- Wardly with respect to the front face of the bolt to permit the rocking of a cartridge as its attitude is altered by said guide grooves.

References Cited in the file of this patent UNITED STATES PATENTS 1,571,592 Loomis Feb. 2, 1926 2,096,028 Burton et a1. Oct. 19, 1937 2,192,677 Hoagland et a1 Mar. 5, 1940 2,342,283 Hyde Feb. 22, 1944 2,483,837 Nettles Oct. 4, 1949 2,601,735 Brush July 1, 1952