US2466578A

US2466578A - Cartridge feeding mechanism

Info

Publication number: US2466578A
Application number: US659985A
Authority: US
Inventors: Corte Alfred
Original assignee: Lockheed Aircraft Corp
Current assignee: Lockheed Corp
Priority date: 1944-12-06
Filing date: 1946-04-05
Publication date: 1949-04-05
Anticipated expiration: 1966-04-05

Description

April 5, 1949. A. CORTE 2,466,578 I CARTRIDGE FEEDING MECHANISM Original Filed Dec. 6, 1944 5 Sheets-Sheet l ALFRED CORTE April 5, 1949. A. CORTE 2,466,578

CARTRIDGE FEEDING MECHANISM Original Filed Dec. 6, 1944 5 Sheets-Sheet 2 ALFRED CORTE pril 5, 1949. A. com 2,466,578

CARTRIDGE FEEDING MECHANISM Original Filed D80. 6, 1944 5 Shet sSheet 3- I I 67 v April 5, 1949. A, QR E 2,466,578

CARTRIDGE FEEDING MECHANISM Original Filed Dec. 6, 1944 5 Sheets-Sheet 4 illfllililli. i

I54 3 I42 [4| I53 ALFRED CORTE 2 Adenf April 5,1949. A. CORTE 2,466,578

CARTRIDGE FEEDING MECHANISM Original Filed Dec. 6,1944 5Sheets-Sheet 5 Patented Apr. 5, 1949 CARTRIDGE FEEDING MECHANISM Alfred Corte, Tampa, Fla., assignor to Lockheed Aircraft Corporation, Burbank, Calif.

Original application December 6, 1944, Serial No. 566,806. Divided and this application April 5, 1946, Serial No. 659,985

Claims.

This invention relates to ordnance, and relates more particularly to automatic or machine guns. A general object of this invention is to provide a machine gun or cannon mechanism embodying a practical dependable cartridge feeding mechanism.

This application is a division of my co-pending application, Serial No. 566,806, filed December 6, 1944.

The mechanism of the present invention is intended for use in a machine gun wherein a live round is Withdrawn from the ammunition belt, then introduced into the cartridge chamber for firing, and following the firing of the round, the empty cartridge case is withdrawn from the chamber and replaced in the ammunition belt. When this sequence is performed in connection With the firing of successive rounds, the ammunition belt is partially emptied and then rebuilt or refilled as it passes through the gun. The re-insertion of the empty cartridge cases in the ammunition belt completely avoids the necessity for providing means to handle the empty cases, and where disintegrating belts are employed, the re-insertion of the empty cases prevents disintegration of the belt so that the continuous belt carrying the empty cases may be readily directed into an appropriate receiver or storage space. If desired, the belt may be reused without the necessity of re-assemblying its individual links. In order to successively withdraw a round from the belt, fire the round and then replace the empty case in the belt, the gun mechanism requires a plurality of bolts for 00- operating with a single barrel extension, with round extracting means associated with the bolts. The present invention is concerned primarily with the cartridge feeding means, the extractor means of the bolt assembly and the associated elements.

It is an object of the invention to provide a cartridge handling mechanism for use with a multi-bolt combination of the character above referred to that is positive, dependable and rapid in operation.

It is a further object of the invention to provide an effective extractor mechanism for the breech bolts, which automatically operates to withdraw the live rounds from the ammunition belt and later insert the empty cases into the belt.

A still further object of the invention is to provide a gun mechanism of the character referred to in which the cartridge sprocket and the multiple bolts are coordinated in a novel manner,

Other objects and features of the invention will be readily understood from the following detailed description of a typical preferred form of the invention wherein reference will be made to the accompanying drawings in which:

Figure 1 is an elevation of the rear portion of a gun embodying the invention;

Figure 2 is an elevation of the forward portion of the gun with certain parts broken away to appear in longitudinal cross section;

Figure 3 is a longitudinal detailed sectional View through the forward portion of the receiver showing the internal parts in elevation;

Figure 4 is a fragmentary longitudinal sectional view of a portion of the gun illustrating the ammunition sprocket and its operating mechanism, and showing portions of the barrel and gas cylinder mechanism in elevation;

Figure 5 is a longitudinal sectional view of the rear portion of the gun with the bolt assembly and a portion of the mechanism for turning the same appearing in elevation;

Figure 6 is a stretch-out view of the drum cam for rotating the bolts;

Figure 6A is an enlarged fragmentary sectional view illustrating the cooking mechanism;

Figure 6B is an enlarged fragmentary sectional view of the firing pin safety means;

Figure 7 is a side elevation of the bolt assembly and its associated actuator;

Figure 8 is a front elevation of the bolt assembly taken substantially as indicated by line B--8 on Figure 7;

Figure 9 is a fragmentary longitudinal sectional View of the actuator assembly taken as indicated by line 9-9 on Figure 8;

Figure 10 is a face elevation of one of the bolts carrying a round and showing the two positions of the, extractors, being a view taken substantially as indicated by line l0|ll on Figure 8;

Figure 11 is an enlarged transverse sectional View of the actuator taken substantially as indicated by line Ill-i! on Figure 7 Figure 12 is a longitudinal sectional view of one of the bolt units;

Figure 13 is an enlarged fragmentary longitudinal section taken substantially as indicated :by line I 3-4 3 on Figure 7 Figure 14 is a front view of one of the'bolts;

Figure 15 is an enlarged transverse sectional view of the actuator, taken as indicated by line l5| 5 on Figure 7 Figure 16 is an enlarged fragmentary sectional view taken as indicated by line l6--l6 on Figure15;

Figure 17 is a fragmentary perspective view of a portion of a bolt. assembly;

Figure 18 is an enlarged side elevation of the barrel extension assembly;

Figure 19 is an enlarged vertical section taken as indicated by line l9-l9 on Figure 18;

Figure 20 is an end view of the barrel extension assembly taken as indicated by line 20-40 on Figure 18;

Figure 21 is a horizontal sectional view of the rack unit'showing the two racks in elevation;

Figure 22 is an enlarged transverse section taken as indicated by line 22-22 on Figure 21;

Figure 23 is a longitudinal detailed sectional view of the barre1 extension assembly takenasindicated by line iii-23 on Figure 20;

Figure 24 is a fragmentary view illustrating the breech latch mechanism;

Figure 25 is a horizontal detailed sectional view of the barrel extension assembly taken as indicated by line 2525 on Figure 20;

Figure 26 is a transverse cross section of the sprocket taken as indicated byline 26--26 on Figure 27;

Figure 2'7 is a side elevation of the sprocket and ammunition belt. assembly;

Figure 28 is a vertical detailed sectional view.

taken as indicated by line 2828 on Figure 3;

Figure 29 is a fragmentary vertical sectional view taken as indicated by line 29-29on Figure 27; and

Figure 30 is a transverse section of one of the racks and its jaws as indicated by line 30-40 on Figure 25.

The features of the present invention may be embodied in ordnance varying considerably .in

caliber and construction. In the drawings the invention. is disclosed in association with a substantially complete gun structure, it being un-.

derstood that the invention is not to be construed as limited to the particular details illustrated and described below.

The gun illustrated includes a housing or receiver 10, which is a relatively stationary component being adapted for support by either a stationary or flexible gun mount. The receiver I0 serves as a support for the various other elements and contains the principal operating parts. As the present invention is not primarily concerned with the construction of the receiver I0, it will sufiice to describe it as an elongate hollow member having generally vertical side walls H, a top wall having a longitudinally extending partially cylindrical crown l2, a bottom wall I3 presenting a cylindrically concave internal surface, and. end walls It and IS. The forward portion of the bottom wall l3 has a rectangular downwardly opening magazine frame l6 for detachably mounting a suitable magazine, not shown. Horizontally spaced guide rods I? extend longitudinally through the receiver I0 to carry the bolt assembly for axial movement as will be subsequently described. While I have referred to the receiver ID as having side walls and top and bottom walls, it is to be understood that the gun may be mounted and employed in any position;

for example, it may be supported so that the parallel walls ll form the upper and lower Walls of the receiver.

The gun barrel 18 extends forwardly from the receiver I0 and is supported for axial movement as required during the recoil and counter recoil phases of operation. The forward wall I5 of the receiver Ill carries a suitable slide bearing unit I9 cooperating with a splined or grooved portion of cartridge case.

the bearing I9 and its mounting form no part of the present invention. The barrel I8 extends rearwardly into the receiver 10 for association with the extension 53 to be subsequently described. A recoil mechanism is provided which includes a tubular jacket 20 secured to the forward end of the receiver H] by screws 2| and extending outwardly in spaced surrounding relation to the barrel I8. The jacket 20 is perforated or slotted for the ready dissipation of heat and its forward end carries a bearing means 22 which assists in supporting the barrel l3 for axial movement. A helical recoil spring 23 is arranged in the jacket 28 in surrounding relation to the barrel E8. The forward end of the spring 23 is engaged by a part 24 of the bearing means 22 which travels with the barrel i8 andv the rear end of the spring 23 bears on a ring 25 which is stationary on the receiver I9; see Figures 2 and 4. With this arrangement of parts, the spring 23 is compressed during recoil movement of the barrel it and the energy stored in the spring during recoil serves to move the barrel and associated parts forwardly for the counter recoil stroke. A

flaring muzzle member 26 is provided on the forward end of the barrel l8 and may contain a suitable flash tube, not shown. It is to be understood that the barrel I8 is suitably rifled and may be of any selected construction and caliber.

Certain elements of the gun mechanism are gas operated; that is, they are operated by a portion of the gas pressure built up in the bore of the barrel 58 when the projectile leaves its A gas cylinder 27 extends in parallel relation with the barrel H3. The cylinder 27 travels with the barrel and enters an opening 28 in the forward wall of the receiver ID. A yoke member 29 engages about the barrel l8 and the cylinder 21 to secure the cylinder to the barrel; see Figure 2. The yoke member is attached to the barrel 58 adjacent the bearing means 22. The forward end of the gas cylinder 2'! is closed and secured to the barrel M3 by a connecting member 35!. Aligned ports 3! and 32 are provided in the forward parts of the barrel l8 and cylinder 2'? and are connected by a tubular junction member 33 engaged about the cylinder and secured on the barrel I8 adjacent its muzzle 26. The ports iii and 32 and the tubular junction member 33 serve to conduct gas pressure from the bore of the barrel iii to the forward portion of the cylinder 21.

A piston 36 is operable in the cylinder 21 and is adapted to be driven rearwardly by the gas pressure conducted to the cylinder from the barrel it immediately following the ejection of the projectile from the barrel. The piston M is closed at its forward end but its major portion is tubular. A tubular piston extension 35 continues rearwardly from the piston to project from the rear end of the cylinder into the receiver ID. A spring 36 is arranged under compression between the closed forward end of the piston 34 and a block 31 slidably engaged in the tubular piston extension 35; see Figure 4. Pins 3!! pass through axial slots in the extension 35 and anchor the block 31 to the wall of the cylinder 2! so that the block forms an effective abutment for the spring. Upon rearward movement of the piston 3% under the action of the gas pressure, the spring 35 is compressed between the rearwardly moving closed end of the piston and the block 31. When the gas pressure is relieved, the energy stored in the spring 36 drives the piston 34 forwardly. The forward and rearward movements of the piston 34 are utilized to translate the bolt assembly, as will be subsequently described.

The gun mechanism further includes a sprocket 39 arranged in the forward portion of the receiver it to handle the ammunition belt B as it moves through the gun. The shape and action of the sprocket 39 will vary somewhat depending upon the nature and caliber of the rounds R. Furthermore, the sprocket 39 may be driven or rotated in various approriate manners to effect an automatic feed of the ammunition belt B. In the construction illustrated, the counter recoil motion of the barrel I8 is employed to intermittently rotate the sprocket 3Q, and the sprocket serves to advance the belt B in timed relation to the elements of the mechanism.

The sprocket 39 is positioned adjacent the magazine frame it, and has its axis of rotation parallel with the barrel. The sprocket 3%! is fixed to its shaft 50, and the shaft is carried by suitable bearings M at the frame it; see Figure 4. Equally spaced longitudinal grooves 42 are formed in the periphery of the sprocket 39 to receive the rounds R, and a circumferential groove 43 is formed in the sprocket to receive the links L of the belt B. The axial grooves 32 are of rearwardly increasing depth to properly receive the projectiles and their cases. The par ticular belt B illustrated is of the non-disintegrating type comprising generally tubular links L interconnected by hinges dd; see Figure 9. As indicated by broken lines in Figure 28, the belt B enters the opening of the frame it, passes 180 around the sprocket 39, and then passes outwardly through the frame opening. It will be observed that the belt B enters and leaves a single side of the gun, thereby greatly simplifying the mounting .of the gun and permitting it to be positioned in confined spaces where only one side is accessible.

The sprocket 39 is rotated substantially 60 during each counter recoil stroke of the barrel I8. The mechanism for producing this intermittent rotation of the sprocket 3E) may take various forms. In the drawings the mechanism for this purpose is illustrated in a more or less diagrammatic manner, and comprises a drum 45 fixed to the forward end of the sprocket shaft 46; see Figure 4. The drum 35 may be positioned in front of the receiver in and may have a suitable casing, not shown. The sprocket rotating mechanism further includes a rod it fixed to the above described yoke 25! to move with the barrel It. The rod lii extends rearwardly to enter the forward end of the drum t5. A flange or collar 4'! is fixed to the rod 6 to operate within the drum. The sprocket drum 4% is provided with six equally spaced axial slots 48. Correspondingly pitched helical slots i9 are formed in the wall of the drum E5 to extend between and connect the adjacent axial slots 53. Pivoted spring urged switches 59 are provided at the junction of the

slots

48 and 69. The switches 5%] occur at the rearward ends of the helical slots 49 and are designed to direct forwardly moving objects in the slots 43 into the helical slots E9. Lugs 5| are provided on the flange ll to move in the

slots

48 and 49, it being preferred to provide a lug 5| for each axial slot. The lugs 5| are diamond shaped to have pairs of parallel sides operable in both the axial slots 38 and pitched slots 49. Pivoted spring urged switches 52 are provided at the forward ends of the helical slots d9 to prevent the lugs 5! from moving into the slots 49 as they travel rearwardly through the straight slots t8.

With the barrel I8 in its forward-most position, the lugs are engaged in the forward ends of the axial slots 48. When the barrel moves rearwardly the lugs 5| moves to the rear in the axial slots and move the switches 5i! out of their paths as they travel rearwardly. The instant the lugs 5| pass the switches 50, the latter swing back to their active positions under the action of their springs. It is to be noted that the engagement of the lugs 5! in the axial slots 48 holds the sprocket 39 against rotation throughout the recoil stroke of the barrel it. When the barrel l8 moves forwardly during the counter recoil stroke, the lugs 5| travel forwardly in the axial slots 48 until they encounter the switches 50. The switches 50 direct the lugs 5! into the helical slots 49 and as the forward movement continues, the lugs travel forwardly in the helical slots. The cooperation of the lugs 5! with the walls of the helical slots 49 rotates the drum 45 and sprocket 39. By the time the lugs 5! move out of the slots d9, past the switches 52, into the adjacent axial slots at, the sprocket 39 will have been turned The re-entry of the lugs 5! into the axial slots t8 definitely terminates rotation of the sprocket 39. Thus during each recoil stroke the sprocket 39 is held stationary, and during each counter recoil stroke the sprocket is rotated 60, and then brought to a stop in a definite angular position.

A barrel extension 53 of special construction is provided for receiving and cooperating with the plurality of bolts 8?. The extension 53 is secured to the rear end of the barrel 18 to operate axially in the forward portion of the receiver Hi and is an integral member provided at its forward end With a tubular boss Mil for receiving the rear end of the barrel l3. The barrel and extension are connected by cooperating interrupted splines 550 and a latch 56!] holds the barrel and extension against relative angular movement in the relationship where the splines are in cooperation.

The extension 53 has a longitudinal opening 55 in axial alignment with the bore of the barrel l8. The major, generally rectangular portion of the extension 53 is cut away at one side, the lower side, as shown in Figures 20 and 23, to provide clearance for the sprocket 39 and other elements.

Lock means is associated with the extension 53 to lock the bolts 81 in the opening 5 for the firing of the rounds. The opposing walls of the extension 53 have aligned generally rectangular windows or openings 55. Lock blocks or jaws 58 are arranged in the openings 55 for movement toward and away from the longitudinal axis of the opening E l. Series of serrations 51 are formed on the inner faces of the jaws and have abrupt forward faces and inwardly and forwardly sloping rear surfaces. An axial groove 58 extends through each series of serrations 51. The end walls of the openings 55 are preferably concave and the ends of the jaws 56 are correspondingly curved to conform thereto.

The lock means further includes a rack mechanism for actuating and retracting the jaws 56. This mechanism embodies a substantially U- shaped member 59 arranged at the rear of the extension 53. Two pairs of spaced rods till are fixed in openings in the member 59 and extend forwardly therefrom to slidably operate in axial openings 6| in the walls of the extension 53. The openings 6| partially intersect the jaw openings 55, so that the rods 60 may cooperate with the jaws. The rods 60 are in the nature of racks having series of rack teeth [52 formed on their opposing sides. The teeth 62 are parallel but are pitched with respect to the longitudinal axes of the rods 60 to be diagonal relative to said axes. The opposite sides of the jaws 55 have correspondingly pitched diagonal teeth 63 meshing with the teeth 62 of the rack rods; see Figures 25 and 30. The direction of pitch or inclination of the

mating rack teeth

62 and 63 is such that upon forward movement of the rods 60 the jaws 56 are moved inwardly relative to the axis of the opening 54 by the cooperating teeth and upon rearward movement of the rods, the cooperation of the teeth moves the jaws outwardly. The engagement of the rack rods 823 with the opposite sides of the jaws 55 normally prevents both inward and outward radial movement of the jaws.

The breech bolt assembly is an important component of the mechanism provided by the invention. This assembly is movable axially in the receiver l and embodies a multiple bolt unit that is intermittently rotated during each complete cycle of operation of the gun. The bolt assembly includes a traveling frame or spider 6 having two elongate tubular bosses 65 which receive and ride on the above mentioned guide rods H; see Figures '7 and 8. The rods El support the bolt assembly for free axial movement. The spider 64 also carries a tube 6% which receives the rear portion of the gas piston extension 35. The piston extension 35 and the tube 66 may have sliding spline engagement to assist in preventing undesirable relative rotation between the parts. The piston extension and the spider tube 66 are related for relative axial movement, and a slack or lost motion connection is provided between these two elements.

The lost motion connection between piston extension 35 and the bolt assembly includes what I will term an actuator til; see Figures 9, ll and 15. The actuator ET is a tubular member surrounding the spider tube 66 and related thereto for axial movement. A longitudinal slot 58 is provided in one side of the actuator 6'5 and the actuator has three circumferentially spaced elongate openings 69 in its wall. Blocks or jaws it are arranged in the openings 69 and are received in elongate axial slots H in the tube 5%; see Figure 9. The jaws 7B are capable of longitudinal. movement in the slots ll whereby the actuator 5'?! may move longitudinally with respect to the bolt assembly. The jaws 7!! may engage the ends of the slots H to limit this relative movement and the end of the actuator 61 engages the spider 64 to assist in limiting the rearward travel of the actuator with respect to the bolt assembly. Teeth or serrations 12 are provided on the inner faces of the jaws T0 to mesh with similar serrations it on the piston extension 35. The engagement of the

serrations

12 and 73 serves to connect the piston extension 35 and the actuator til. The jaws I0 are movable radially in the openings 59 and means are provided to yieldingly urge the jaws outwardly so that their serrations '52 will not interfere with the insertion of the piston extension 35 into the tube 66. External circumferential grooves H! are provided in the actuator 6i and intersect the openings 69. Partially circular springs i5 are arranged in the grooves "i l and have their ends anchored to the actuator. The springs l5 pass through openings in the end portions of the jaws IE to urge the jaws outwardly. In addition to urging the jaws to their outward positions, the

S springs 15 hold the jaws assembled in the actuator 61.

Cam means is provided to normally hold the jaws H1 in their inward positions where the teeth 12 and E3 cooperate to secure the actuator 61 to the piston extension. An internal circumferential groove lit in the actuator 51 carries a partially circular cam member 11. The inner surface of the member ll has spaced cam lifts 18 which are cooperable with the outer sides of the jaws ill. Upon turning of the member H in one direction lifts 18 may be brought into cooperation with the jaws ill to force them inwardly and bring the teeth "52 into engagement with the teeth 13. The cam member H is movable between the position illustrated in Figure 11 where the lifts 'i8 hold the jaws i0 inwardly and a position where the springs 15 may return the jaws to their outward positions. Latch or detent means are provided to releasably hold the member in its two positions. Detents is are formed on the exterior of the member Ti and are cooperable with shoulders 38 on the actuator 61. The cam member I? may be turned to a position r where one detent engages the adjacent shoulder 8ft to releasably hold the member where the jaws 'lii are retracted. Openings Si in the wall of the actuator 6'! are adapted to receive the detents "E3 to retain the cam member H in the position where the jaws T0 are actuated. The detents 19 have sloping surfaces whereby they may be readily released from the openings 8! to allow the cam member H to be moved to the position where the jaws 1E1 are released. The cam member 11 is slotted circumferentially at each side of the detents E9 to provide the flexibility and resiliency necessary to snap the detents into and out of cooperation with the shoulders and open ings 6!. It will be seen that upon depressing the detents E9 the cam member '17 may be turned between its two positions to actuate and release the toothed jaws iii. The releasable slack connection between the bolt assembly and the piston extension 35 afforded by the actuator 6'! described above, is such that the bolt assembly is moved rearwardly and forwardly with each full cycle of operation of the piston 34 by the gas pressure and spring 36. The lost motion allowed by the construction described above serves to control the sear and hammer mechanism and to permit other actions to be subsequently described.

The bolt assembly further includes a tube 82 threaded in an opening in the spider 64 to extend forwardly from the spider in parallel relation to the barrel Hi; see Figure 13. A shaft 83 extends through the tube 32 and is supported for rotation therein by spaced bearings 8d. A ring 85 is keyed or otherwise fixed to the forward portion of the shaft 83 to carry the bolts and a similar ring 86 is fixed to the rear portion of the shaft 83 for a purpose to be later described. The bolts 81' are fixed to the ring 85 to be equally spaced circumferentially and to be in parallel relation to the barrel 58. In the particular gun illustrated there are three bolts 81 spaced apart. Projecting arms 33 on the rotatable ring 85 carry the three bolts ill. The bolt assemblies are identical and I will proceed with a detailed description of one of them, it being understood that this description applies to all of the bolt units.

Each bolt 8] includes an elongate body 89 that is generally rectangular in transverse cross section. The bolt body 89 is proportioned to readily enter the opening 54 of the barrel extension 53 and is provided at its opposite sides with serrations 90 for cooperating with the serrations 5'I of the jaws 56. The serrations 90 have abrupt rear faces for looking with the abrupt forward faces of the serrations 51, and have outwardly and rearwardly sloping forward surfaces for engaging the slopin faces of the teeth 5?. Lon.- gitudinal slots HI are provided in the bolt body 89 for the purpose which will later become apparent, and extend through the sets of serrations 90 to divide the serrations in spaced series Upon forward movement of the bolt assembly, the bolt 8i, which is aligned with the barrel It, enters the opening 54 and introduces the new round into the firing chamber 92.

Each bolt IB'I is equipped with extractor means for extracting a round R from the ammunition belt B and for retaining the round as the belt moves rearwardly and then forwardly so that the round is introduced into the firin chamber. The extractor means further serves to withdraw the empty case following firing the round and later introduces the empty case into the belt B. The extractor means includes pawls 94 extending through the grooves 9i to be partially contained and guided therein. The above mentioned grooves 58 in the breech jaws 55 receive the protruding portions of the pawls 94; when the bolt is locked in the barrel extension. The pawls 94 extend beyond the forward ends of the bolt body 55 and their projecting portions have beveled noses 95 provided with the internal shoulders 95 for engaging and gripping the flange 91 at the base of the cartridge case. The

shoulders 80 are arcuate and abrupt to conform to the flange 9? and the forward internal surfaces of the pawl noses 95 slope away from the shoulders so that the noses may snap over the flange. The forward end of the bolt body 89 has a circular depression 08 for receiving the flange 91 of the cartridge case, and the pawl noses 05 extend into the socket for cooperation with the flange.

The rear portions of the extractor pawls 94 are mounted for movement and a mechanism is provided to impart a combined forward and lateral motion to the pawls to free the noses 95 from the flanges ill of the empty cartridge case after the latter has been reinserted in the ammunition belt B. The bolt body as has a longitudinal opening 90 and a tube I enters the rear end of the opening. The tube I00 is secured in the openin 09 by transverse pins IIJI engaged in openings in the bolt body and cooperating I with notches in the tube. The tube I053 extends beyond the rear end of the body 89 and has a T-head which is notched at its ends to form split lugs I52; see Figure 17. The pawls 9d have reduced end portions which are slidably received in the lugs 32. Pins I03 are engaged in transverse openings in the rear corner portions of the body 85 and pass through the grooves 9|. Forwardly and laterally inclined slots I04 are formed in the pawls 94 and receive the pins I53; see Figure 12. The cooperation of the pins Hi3 and slots I0 1 directs the pawls Ila forwardly and outwardly when actuated.

The means for operating the pawls 94 further includes yoke-like actuators I which straddle the lugs I52, and the adjacent portions of the pawls. Pivot pins I00 are engaged in openings in the actuators I05 and the pawls 94 to pivotally connect these elements. The split lugs I02 have transverse openings I01 registering with longitudinal slots I08 in the rear portions of the pawls 94. The side walls of the actuators I05 have rearwardly and laterally inclined slots I09 which register with the openings I0'I. Pin-s IIO pass through the slots I09, the openings I0? and the longitudinal slots I 08. The engagement of the pins I I0 in the openings II]? of the rigid lugs I02 restrains the pins against bodily movement. When the rear portions of the actuators I05 are pressed inwardly toward the longitudinal axis of the bolt body 89 the cooperation of the inclined slots It!) with the pins IIO cams the actuators forwardly. The intermediate pins I06 being engaged in. confining openings in the actuators and pawls 95, transmit this forward movement to the pawls. The engagement of the inclined slots I04 of the forwardly moving pawls 94 with the pins I03 imparts a forward and outward direction of movement to the pawls. This movement disengages the pawl noses from the flange 91 freeing the bolt from the empty case.

Means is provided to normally urge the actuators I05 to positions where the pawls 94 are in active gripping engagement with the round flange 97. This means includes a sleeve III slidable on the tube I00 and forked at its rear end to partially straddle the side parts of the actuators I05 and to present rearwardly facing shoulders II 2. The actuators I05 have forwardly facing hooks H3 engaging the shoulders '2. A spring II 4 surrounds the tube I00 and is engaged under compression between a shoulder on the wall of the opening 99 and the forward end of the sleeve III. The spring IIII urges the sleeve III rearwardly so that the cooperation of the shoulders H2 with the hooks II3 pivots the actuators I 05 outwardly or laterally. The spring I I4 normally holds the actuators I05 in the positions where the pawls 94 are fully actuated.

Any appropriate means may be provided for actuating the extractor pawls 94 to free their noses 95 from the cartridge flanges 91. In the simple case illustrated, cam projections H5 are suitably located on the walls of the receiver I0 to be engaged at the proper time by the actuators I05. The outer surfaces of the pawl actuators I05 are inclined rearwardly and laterally, and upon contacting the cams I I5, produce inward movement of the actuators toward the longitudinal axis of the bolt assembly. As above described, this movement results in forward and lateral movement of the pawls 95 to open their round-gripping noses 95. It is to be understood that other means may be utilized to operate the pawl actuators I05, and the invention is not to be construed as limited to the use of the cams H5 but is to be considered as contemplating any practical operating means.

Each bolt 81 further includes a firing pin H6 and a novel safety means for the pin. The firing pin H6 is arranged longitudinally within the tube IIIII and is capable of limited axial movement. Its forward end portion is pointed and operates in a reduced opening I I1 leading to the forward end of the bolt body 89. A flange II8 on the pin II 6 is engageable with the forward end of the tube I00 to limit the rearward travel of the pin and may engage a shoulder on the wall of the opening II 1 to limit the forward travel of the pin. A spring H9 surrounds the pin H6 and is engaged between a rearwardly facing internal shoulder in the tube I00 and a sleeve I20 surrounding the-rear portion of the firing pin. The rear end of the pin H5 is exposed at the end of the tube I00. The above-mentioned safety means includes the sleeve I20 surrounding the rear portion of the firing pin H6 and slidable within the tube we, tially spaced longitudinally extending grooves I2I is provided in the rear part of the firing pin I16 to be within the sleeve I226. The end walls of the grooves I2I curve or slope outwardly to the periphery of the pin HE. A ball I22 operates in each groove I2l and rides on the internal surface of the sleeve I28. The rear end of the sleeve I20 is exposed at the end of the bolt body 89 and may be projected slightly from the end of the firing pin. The spring III: urges the sleeve I2Il to the rear and the balls I22 engage the end walls of the grooves I2I to limit rearward travel of the sleeve relative to the pin I I6 and to transmit the rearward spring pressure to the pin. In

A series of circumferenthe event that the firing pin [I6 is moved for- I wardly independently of the sleeve I, the balls I22 ride up the sloping end walls of the grooves I2I and bind to prevent actuation of the firing switches I32. are provided at the forward ends of the helical slots I29. The switches I32 are pivoted and spring urged to positions where they prevent the lugs I39, traveling rearwardly through the axial slots I23, from entering the helical slots.

Upon rearward movement of the gas piston 32, the lugs I36 travel rearwardly through the axial slots 28 from the forward ends of the slots to their rear ends. This engagement of the lugs in the slots I23 prevents rotation of the bolts Ell and assures true rearward movement of the bolts so that the bolt in the barrel extension 53 moves out of the same without interference and the bolt that has. engaged the new round It in the belt E withdraws the round from the belt I28 and are prevented from entering the helical pin. However, when the sleeve I20 is struck first, I

or when the sleeve and the firing pin are simutane'ously moved forwardly, the balls I22 remain in intermediate positions and the firing pin is free to operate.

During each reciprocation of the bolt assembly its three bolts 81 are turned as a unit a distance of i20 to provide for the required sequence of round extracting, insertion of the round into the firing chamber 92 and the insertion of the empty cartridge case into the belt B. The present invention is not primarily concerned with the except as such means may occur in combination with the elements of the invention, and it is con. templated that the bolts may be rotated by anyappropriate means actuated either by the gas cylinder mechanism or by the recoil or counter recoil of the barrelIB.

In the drawings there is illustrated in a more or less schematic manner, one means for producing the required rotation of the bolts 81 during the forward stroke of the gas piston 34. This means includes a tubular drum I25 secured to the rear wall I I of the receiver I0 and a tube or rod I26 secured to the shaft 83 of the rotatable bolt unit and extending rearwardly into the drum. Ifdesired, the rod I26 may be a simple extension of the shaft. A collar or flange I2! is fixed to the rod I26 and operates in the drum I25. Three axial slots I28 spaced 120 apart are provided in the walls of the drum I25. The slots I28 are connected by pitched or helical slots I29. The slots I28 and I29 are of uniform width and are adapted to slidably receive lugs I3!) formed on the periphery of the flange I21. There is a lug I30 for each axial slot I28 and the lugs have pairs of parallel side surfaces adapted to slidably ride along the walls of the axial slots and helical slots. The helical slots I29 join the rear end portions of the axial slots I28. Each helical slot I29 extends from immediately adjacent the rear end of one axial slot to join the next axial slot a relatively short distance from its rear extremity. This leaves the major forward portions of theaxial slots I28 entirely uninterrupted. A pivoted switch I3I is provided at the rearmost end of each helical slot I29. The switches I 3| are spring urged to the positions illustrated in Figure 6 where they direct the lugs I3Il from the axial slots I28 into the helical slots when the lugs are traveling forwardly. The switches I3I are swung out of the way by the lugs as the lugs travel rearwardly in the axial slots I28. Similar slots E29 by the switches I32. When the bolt assembly begins to move forwardly under the 110'! tion of the spring 35, the lugs I30 almost immediately encounter the switches HI and are diverted thereby. into the helical slots I229. The

lugs Iilil travel forwardly through the helical slots I29 and their engagement with the slots of the stationary cam drum I25 produces rotation of the bolt assembly through a distance of 120.

means for effecting this rotation of the bolts 8'1,

Owing to the pitch of the slots I29, this rotation of the bolt assembly is rather abrupt and the angular movement is completed by the new round carried by the bolt 81, which is being brought into alignment with the barrel before the round can interfere with the barrel extension 53 or the parts associated therewith. Upon leaving the helical slots I29, the lugs I36 engage the switches I32 and swing them out of the way; Upon passing out of the slots I29, the lugs I30 move forwardly inthe axial slots I28 and remain in the axial slots until the forward stroke of the gas .iston, has been completed. The engagement of the lugs I39 in the axial slots I28 definitely maintains the bolts 8'! in the angular position where the new round is in alignment with the barrel, and where the empty cartridge case is aligned with its empty belt link L for insertion therein. It is to be observed that the bolt assembly is turned in the same direction as the sprocket 39 but is turned. with each complete cycle whereas the sprocket is turned only 60.

The above described jaws 56 of the barrel extension 53 and rack mechanism for operating the ja are latched in positions where the bolt 81 carrying the new round R may freely enter the extension upon forward movement of the bolt without interference by the jaws 56. The latch mechanism for holding the jaws retracted is released or conditioned for release during forward movement of the gas piston 34 by a part associated with the above described actuator B1. The latch means includes a tube I33 fixed in an opening I34 in the intermediate portion of the member 59. The tube I32 projects forwardly to extend along one side of the extension see Figures 18 and 23. The tube I33 is slidably guided in openings I35 of spaced lugs I26. The parts are related so that the tube I33 remains in, cooperation with the openings I25 throughout the entire range of movement of the rack supporting member 59. A sleeve I2! surrounds the tube IM and has an internal shoulder I38. The sleeve I31 normally bears rearwardly against the rear lug I35. A spring I39 is arranged under compression between the forward lug I36 and shoulder I38 to urge the tube I33 ceiving a latch MI.

and sleeve I31 rearwardly. The spring I39 is of sufficient strength to normally hold the member 59 in its rearmost position where the jaws 56 are fully retracted.

The tube I33 has an elongate axial slot Mi re- The latch has an inwardly projecting ear I42 on its inner edge received in a notch I43 in the sleeve I37 and operating in an axial slot I M in the Wall of the barrel extension 53; see Figures 23 and 24. An annular groove M is formed in the exterior of the sleeve I31 and receives a wire ring I 56. The ear M2 of the latch has a transverse opening I5! and the ring I46 passes through the opening to retain the latch MI in the slot me; see Figure 19. The latch I ll also has a projection I48 on its forward end freely received in the opening of the tube 153. An ear M9 projects from the outer edge of the latch MI and is engaged by the rear end of the sleeve I51. The spring urged sleeve I35, acting on the forward edge of the latch MI and its ear M9, normally urges the latch to the full line position of Figure 23. The longitudinal outwardly facing edge of the latch MI has an abrupt shoulder I553 facing rearwardly. The shoulder I5I! is pitched forwardly and inwardly to some degree when the latch I4! is in the normal full line position of Figure 23. The same edge of the latch I5! has a shorter forwardly facing shoulder i5! which is also pitched forwardly and inwardly. The rear end surface I52 of the latch is engageable with the end wall of the slot I40 to normally prevent forward movement of the member 59 and its rack rods 60 relative to the barrel extension 53. This surface of the latch is slightly inclined and rounded away so as to clear the end wall of the slot I40 and enter the tube I33 upon slight swinging movement of the latch Isl in the direction indicated by the arrow in Figure 23. The inner edge of the latch MI has a sloping shoulder I53 engageable with the rear end of the extension 53. It will be seen that the spring 539 holds the latch M I in the full line position of Figure 23 where the surface I52 engages the end wall of the slot Hill to positively prevent forward movement of the member 59 and rack rods 55 so that the jaws 55 are retained in their retracted positions.

Means is provided for releasing the latch MI just prior to forward actuation of the rack member 59. This means includes a rod I55 carried by the actuator 61. The actuator has a yoke I55 open to its interior and the rod I54 is provided with a grooved flange I56 seated in the yoke so as to be normally rigid with the actuator. The engagement of the flange I56 in the yoke I55 positively holds the rod I54 against angular movement. The rod I54 extends both forwardly and rearwardly from the yoke I55, and its longitudinal axis is coincident with the axis of the tube I33. During the final portion of forward motion of the gas piston 34 and the actuator 51, the rod I5 5 enters the tube I33. The above described notch 58 in the actuator freely clears or passes the lugs I36 during this movement. The advancing end of the rod I54 may be somewhat beveled to readily enter the tube I 33. One side of the rod I54 has an inwardly facing notch I51 and is cut away to some extent to clear the rear portion of the latch I M when entering the tube. The

end of the forwardly moving rod I55 is adapted rod I54. The engagement of the rod I54 with the shoulder E55 may not be sufficient to cause the latch to swing the entire distance, but the cooperation of the rear wall of the slot I40 with the rounded end surface I52 of the latch com pletes the swinging of the latch. When the latch MI has been swung to the position of Figure 24, the rack rods 68 are free to move forwardly and actuate the jaws 55 to cooperate with the bolt serrations 90. It is to be observed that during forward movement of the bolt assembly the actuator 51 is in its forward position relative to the spider because the actuator is, in effect, pulling the spider and bolt assembly forward. Accordingly, the latch MI is released or conditioned for release by the rod I54, on the leading actuator, before the yoke I55 engages the member 59 or before the spider 64 of the bolt assembly comes into contact with the yoke I55. When the bolt assembly is drawn forwardly by the actuator 5?, the rod I55 first releases or conditions the latch I5I for release and the yoke I55 then engages the member 59. The spider 64 moves up to its final position to introduce the bolt 81 into the barrel extension 53, inertia carrying the bolt assembly forward while the actuator lags slightly by reason of its engagement with the latch. The actuator continues to move forwardly after the spider stops. and the actuator strikes the member 59, to drive the rack pins 50 forwardly and actuate the jaws 56.

When the jaws 56 are fully actuated, the latch I5I is in the position illustrated in Figure 24. With the latch in this position its end surface I52 is engaged with the rear wall of the notch I51 to hold the member 59 and the rack rods 60 against rearward movement. Thus the latch MI effectively locks the jaws 56 in the position where they retain the bolt 8'5 in the barrel extension. Rearward movement of the rod I54 by the action of the gas piston 52 immediately following firing of the round moves the forward wall of the notch l5"! against the pitched or rounded shoulder I5I of the latch to release the latter. Upon release of the latch I M, the spring I39 moves the rack rods 55 to the rear with the result that the jaws 55 are retracted. Retraction of the jaws 56 is immediately followed by rearward withdrawal of the bolt 8? from the barrel extension by the gas piston 35 acting through the medium of the actuator 5?.

Immediately following locking of the bolt in the barrel extension, the firing pin I I5 of the bolt 81, in the extension, is operated to fire the round B. Each bolt 87 carries its own firing pin H6 to be in a position for actuation by a suitable hammer mechanism. The invention is not primarily concerned with the nature of the hammer mechanism employed except insofar as it occurs in combination with the other elements. In order to complete the disclosure I have illustrated a hammer and cocking mechanism including a tube I59 secured to the spider E i and arranged to receive the rear portion of the above described rod I 54; see Figure 6A. A sleeve I55 is slidable on the tube I59 and carries a laterally projecting hammcr I5I. The ring 36 on the rear of the shaft 83 carries three spaced projections I52 provided with axial grooves I633. The axial slots I28 of the cam drum i25 position the ring 85 so that the grooves I53 of its lugs I62 are successively aligned with the hammer I5I. A bushing IE4 is secured in an opening in the spider 54 and slidably carries a striking pin I55. The parts are related so that the pin I55 is aligned with the hammer 15 [6| and the pin is normally urged to the rear by a light spring 65. The hammer lf'il, when actuated, moves through a guide groove ltd and strikes the pin I55, which in turn, strikes the sleeve l2!) and firing pin H6 of a bolt assembly to fire the round R.

The means for actuating the hammer I5! in cludes a spring iii? arranged under compression between the sleeve i 60 of the hammer and a head IE3 on the rear end of the tube 5%. The spring l6! surrounds the tube 459 and is adapted to drive the sleeve E68 and the hammer N53 forwardly with considerable force. An arm ltd pro- ,iects radially from the rod ISA and operates in a slot Its in the tube lbs. The sleeve Hill of the hammer has a stop lug IlI on its forward end engagoable with the securing flange of the tube I59 to limit the forward movement or the hammer sleeve Hill and stop it in a position where the arm M39 is directly in front of the sleeve.

When the gas piston M begins to move rearwardly, the actuator 61 moves rearwardly with respect to the spider 6 s and the rod I5 moves rearwardly in the tube 59. During this relative movement between the rod I5 and the tube I59 the arm I59 moves the sleeve I60 rearwardly along the tube to compress the spring I 61. A pivoted spring urged latch I72 is carried in a slot in the tube I59 and engages in a notch I'EZ in the hammer sleeve 166 to releasably latch the hammer in its cocked position; see Figure 6A. This occurs immediately before the actuator 61 engages the spider M to push the spider and bolt assembly rearwardly. The latch I'l2 holds the hammer i6! stroke of the bolt assembly and during the major part of the forward stroke of the assembly. Before the gas piston 3 t reaches the end of its forward movement, the rod I54 engages the shoulder I59 of the spring-held latch MB and this causes the actuator 6i and the rod i 5 5 to lag slightly. The inertia of the spider 6t and the bolt assembly carries the spider forwardly relative to the lagging rod led to actuate the rack rods 68 and jaws 58 as above described. The actuator El and the rod i5 3 continue to move forwardly under the action of the gas piston spring 35 after the spider M has stopped its for- Ward movement. This final short forward motion of the rod Hid relative to the tube I59 brings a cam I'M on the rod into cooperation with the latch M2 to release the latch. Upon the release of the latch N2, the spring It? drives the hammer It! forwardly to strike the pin 565, which in turn, strikes the firing pin H6 and sleeve I20 to fire the round R. The spring urged latch I12 automatically returns to its active position and the cam lid moves away from the latch during the subsequent rearward motion of the rod I54 relative to the tube l59.

Any appropriate means may be employed to charge the gun manually and to initiate and terminate gun operation. For example, a cable Iili shown schematically, may be connected with the spider fi l of the bolt assembly and extend to the exterior of the receiver Hi to provide for hand charging of the gun by pulling the bolt assembly rearwardly to thus compress the gas piston spring 36 and rotate the bolts 3! to their new angular positions. A suitable solenoid operated mechanism may control the hammer and cooking means to initiate and terminate operation of the gun. Such solenoid control mechanisms are common in the art, and form no part of the present invention and are therefore considered cocked during the rearward unnecessary to an understanding of the construction provided by the invention. This invention is concerned with the cartridge feeding means and bolt assembly combination and elements associated therewith, and while a substantially complete gun has been disclosed it is to be understood that this disclosure has been provided for the purpose of assuring a better understand ing of the construction and operation of the novel features and is not to be considered as restricting either the scope or the application of the invention.

Operation Substantially complete operation of the gun will be described below in order to fully disclose the purpose and operation of the barrel extension and bolt assembly. To condition the gun for operation a suitable magazine, not shown, is applied to the frame it and the ammunition belt B is trained over the sprocket 39. At least one link L of the belt B is empty so as to pass the barrel extension 53, and a live round is introduced into the recess in the forward end of the bolt iii, which is to be aligned with the barrel, so as to be gripped by the pawl noses 95. When the sprocket 39 has been supplied with the belt B, the bolt assembly is manually moved to the rear by the charging cable I96. During the rearward travel of the spider 6 3 and bolt assembly, the

hammer liil is cocked as above described. The

lugs I36 travel rearwardly through the axial slots I33 and the bolts Bl move rearwardly without rotation. The rearward movement of the actuator 6? with the bolt assembly causes rearward travel of the gas piston 34 and the spring 36 is compressed so that energy is stored therein. Upon completion of rearward travel of the bolt assembly the gun is ready for operation.

The bolt assembly may be released for forward movement under the action of the spring 36 by a suitable control device, either direct or remote. For present purposes it may be considered that the operator merely releases the charging cable to allow the spring 38 to move the bolt assembly forward. During the first phase of forward movement of the spider 64 and bolt assembly, the lugs I 39 move through the helical slots I29 to rotate the bolts 120. This brings the bolt 81, which is carrying the live round, into alignment with the firing chamber 92. During the remainder of the forward motion of the bolt assembly, the bolts are held against rotation and the bolt 58?, carrying the round, enters the barrel extension. The actuator pawls 96, of an empty bolt 81, cooperate with the next round in the belt B to have their noses 95 grip the flange 91 of the round. As above described, the rod I54 enters the tube I33 and contacts the latch shoulder I50 to release the latch HM so that the member 5% and the rods 6i) may move forwardly to operate the jaws 56. The latch M! operates to retain the member 59 and the rods (it in their forward positions where the jaws 56 are actuated so that the bolt 81 is locked in the barrel extension. During the final phase of forward movement of the bolt assembly and actuator 61, the cam I'M releases the latch I12 and the hammer I6! is actuated to fire the round.

Upon firing of the round, the gas pressure developed in the bore of the barrel I8 acts on the gas piston 34 to drive it rearwardly. Rearward movement of the gas piston moves the actuator 6 to the rear. This releases the latch MI as described above so that the spring I39 may move the rack rods 60 to the rear and retract the jaws 56. The initial'rearward movement of the actuator 6'! also compresses the hammer spring I61 and cocks the hammer I I. Thus by the time the rearward travel of the actuator 61 relative to the spider 64 iscompleted the jaws 56 are retracted to release the bolt 81 and the hammer IBI is cocked. The actuator 61 then engages the spider 64'tomove the bolt assembly to the rear. During rearward movement of the bolt assembly the lugs I30 move through the'axial slots I28. The rearward movement of the bolt assembly also results in withdrawal of the empty cartridge case from the firing chamber 92 and the new round gripped in the pawls 94 of a bolt 81 is pulled out of the belt B. Thus one empty cartridge case and one live round are moved to the rear with the bolt assembly. During the recoil of the barrel I8, accompanying firing of the round, the lugs 5| travel rearwardly through the axial slots 48 and the sprocket 39 remains stationf Upon counter recoil of the barrel IS, the lugs 5| move through the helical slots 49 to rotate the sprocket 39 and thus position the sprocket to receive the empty cartridge case and to bring the next round into position for extraction by the pawls of the now empty bolt 81. The spring 30 initiates forward movement of the bolt assembly immediately following rearward travel of the assembly. During the forward stroke of the bolt assembly, the lugs I30 cooperate with the helical slots I20 to turn the bolt assembly to the position where the new round is aligned with the firing chamber 92 and the empty cartridge case is aligned with its empty link L of the belt B. The lugs I30 move into the axial slots I28 and during the remainder of the forward motion of the bolt assembly the bolts are held against rotation. During the final phases of forward motion of the bolt assembly, the new round R is introduced into the firing chamber 92 and the bolt 81 enters the opening 54. The rod I54 of the actuator assembly releases the latch I4'I so that the jaws 56 may be actuated to lock the bolt in the barrel extension. The empty cartridge case is introduced into the empty link L of the bolt during the final forward motion of the bolt assembly, and the actuators I05 of the bolt 81, which carries the empty cartridge case, are operated through engagement with the cams II5 so that the pawls 94 release the empty case. The pawls 94 remain in the released condition until the bolt assembly begins its rearward travel during the next cycle of operation and the released pawls allow the empty case to remain in the belt B. The final phases of forward movement of the actuator 6! release the latch I14 so that the hammer I6I is actuated to fire the round. The above sequence of operations is repeated during successive automatic firing cycles of the gun.

Having described only a typical form. of the invention, I do not wish to be limited to the specific details herein set forth, but wish to reserve to myself any variations or modifications that may appear to those skilled in the art or fall within the scope of the following claims.

I claim:

1. In a gun having a barrel and a rotatable sprocket for handling a cartridge belt, a mechanism comprising an extension for the barrel, a substantially annular series of breech bolts supported for intermittent rotation about an axis parallel with the barrel, means for supporting the series of bolts for movement axially of the barrel and sprocket whereby the individual bolts may be moved into and out of the extension, means 1m- 18 parting such. axial movement to th series of bolts, mechanism for imparting said intermittent rotation to the series of bolts during such axial movement, and extractor means on each bolt operable to withdraw a cartridge from the belt and introduce it into the extension upon said axial movement and rotation of the bolts.

2. In a gun having a barrel and a rotatable sprocket for handling a cartridge belt, a mechanism comprising an extension for the barrel, a substantially annular series of breech bolts supported for intermittent rotation about an axis parallel with the barrel, means for supporting th series of bolts for movement axially of the barrel, and extractor means on each bolt operabl to extract a cartridge from the belt and introduce it into the extension upon said axial and rotary movement of the bolts, and means for imparting such intermittent rotation and axial movement to the bolts.

3. A gun comprising a barrel having an extension, a sprocket for handling an ammunition belt and rotatable about an axis parallel with the barrel, a carrier movable forwardly and rearwardly relative to the barrel and sprocket, a substantially circular series of bolts, means for mounting the bolts on the carrier for rotation about an axis parallel with the barrel, means for moving the carrier forwardly and rearwardly, means for rotating the series of bolts during said movement of the carrier to move one bolt into alignment with the barrel and to move another bolt into alignment with a given point on said belt, and extractor means on the bolts operable to extract ammunition from the belt and introduce it into the barrel extension during said rearward, forward and rotary movement of the bolts.

4. A gun comprising a barrel, a sprocket for handling a cartridge belt and rotatable about an axis parallel with the barrel, a carrier movable forwardly and rearwardly relative to the barrel and sprocket, a substantially circular series of three spaced breech bolts, means for supporting the series of bolts on the carrier for rotation about an axis parallel with the barrel, extractor means on each bolt for gripping and retaining cartridges, means moving the carrier forwardly and rearwardly, and means for rotating the series of bolts during each cycle of forward and rearward movement so as to align one bolt with a cartridge in the belt to have the extractor means of said bolt grip the cartridge during forward movement, to align the second bolt with the barrel to have a cartridge carried by the extractor means thereof introduced into the barrel during forward movement and to align the third bolt with a given part of the belt to have an empty cartridge case carried by said third bolt introduced into the belt during forward movement of the carrier.

5. In a gun mechanism having a barrel, the combination of, a sprocket for handling an ammunition belt, said belt being adapted to carry live and empty cartridges, means for supporting the sprocket for rotation about an axis parallel with the barrel, a carrier supported for axial movement substantially parallel with the barrel, an annular series of bolts, means for supporting the series of bolts on the carrier for rotation about an axis parallel with the barrel, an extractor means on each bolt operable to extract a cartridge from th belt and introduce it into the barrel upon axial movement of the carrier and rotary movement of the series of bolts, and means 20 REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date Schwartzlose Aug. 13,1907 Page June 5, 1928 Williams June 11, 1940