US2950653A

US2950653A - Bolt assembly for a firearm

Info

Publication number: US2950653A
Application number: US719172A
Authority: US
Inventors: Earle M Harvey
Original assignee: Individual
Current assignee: Individual
Priority date: 1958-03-04
Filing date: 1958-03-04
Publication date: 1960-08-30
Anticipated expiration: 1977-08-30

Description

ug. 30, 1960 E. M. HARVEY BOLT ASSEMBLY FOR A FIREARM 3 Sheets-Sheet. 1

Filed March 4, 1958 Aug. 30, 1960 E. M. HARVEY BOLT ASSEMBLY FOR A FIREARM Filed March 4, 1958 3 Sheets-Sheet. 2

i ne

ug. 30, 1960 E. M. HARVEY BOLT ASSEMBLY FOR A FIREARM 5 Sheets-Sheet 5 Filed March 4, 1958 INVENTOR.

En1.\1& rl Hu-Vey BOLT ASSEMBLY FOR A FIREARM Earle M. Harvey, Agawam, Mass., assigner to the United States of America as represented by the Secretary of the Army Filed Mar. 4, 1958, Ser. No. 719,172

3 Claims. (Cl. 89-185) (Granted under rl`itle 35, US. Code (1952), sec. 266) The invention described herein may be manufactured and used by or for the Government for governmental purposes without the payment of any royalty thereon.

This invention relates to automatic firearms and more particularly to bolt mechanisms therefor.

It is one of the objects of this invention to provide for automatic firearms a bolt mechanism which is substantially symmetrical in configuration and in which the operating forces are uniformly distributed to eliminate as much as possible those vibrations which might adversely affect the accuracy of the firearm.

It is another object of this invention to provide for firearms a bolt mechanism in which the operating parts are held in Iunitary relationship without the need of pins or other similar securing means and is readily disassembled for inspection and repairs.

It is still another object of this invention to provide a bolt wherein a central body portion is rotatable between a lock and an unlock position while the head portion is restrained from rotation so that torque is not applied to a cartridge while vbeing chambered and extracted.

It is -a still further object of this invention to provide a bolt mechanism provided with a pair of diametricallyopposed extractors pivotally mounted in a nonrotating head whereby uniform force is applied between the cartridge and the bolt during the chambering and extracting operations.

lt is another and still further object of this invention to provide a bolt `mechanism in which such nonrotating head and pair of extractors cooperate with the ejector for ejecting the fired cartridge case from the lirearm uniformly and Without spinning by being slid rather than rotated out of disengagement with the extractors as with conventional devices.

It is still another and further object of this invention to provide a bolt mechanism in which the striker mechanism is held against rotation by the ejector and is cocked by rotation of the body portion relative to the striker mechanism through the cooperation of a pair of diametrically-opposed rollers mounted to the firing pin with cam recesses provided in a striker extension joined to the head by the ejector and held thereby against rotation.

It is still a further object of this invention to provide a striker device which is assembled into a single unit and is easily disassembled from the bolt.

The specific nature of the invention as well as other objects and advantages thereof will clearly appear from a description of a preferred embodiment as shown in the accompanying drawings in which:

Fig. l is a cross-sectional side View of the firearm showing the bolt in locked battery position;

Fig. 2 is a view similar to Fig. l but showing the bolt in the recoil position and a fired cartridge case ejected therefrom;

Fig. 3 is a View similar to Figs. l and 2 but showing the bolt in ramming engagement with a cartridge partially removed thereby from the magazine;

g 2,950,653 Patented Aug. 30, 1960 Fig. 4 is a cross-sectional view of the bolt showing the correlation of the parts in the striker mechanism when held in retracted position;

Fig. 5 is a view taken along line 5-5 of Fig. 2;

Fig. 6 is a view taken along line 6 6 of Fig. 1;

Fig. 7 is a view taken along line 7-7 of Fig. 5;

Fig. 8 is a view taken along line 8-8 of Fig. 4;

Fig. 9 is a view taken along line 9--9 of Fig. 4;

Fig. 10 is an exploded perspective View of the boltcarrier group;

Fig. 11 is an exploded perspective view of the bolt;

Fig. 12 is an exploded perspective view of the striker assembly;

Fig. 13 is a cross-sectional side view of an alternate ejector showing the ejector in normal position;

Fig. 14 is similar to Fig. 13 but showing the ejector in ejecting position;

Fig. l5 is a front view of the bolt showing the alternate ejector mounted thereto; and

Fig. 16 is an exploded perspective view of the alternate ejector.

Shown in the figures is a firearm provided with a tubular receiver 12 and a barrel assembly comprising a barrel 14 and a cylindrical barrel extension 16 which is threadably mounted to the front end of the receiver so that the axis thereof coincides with the axis of the barrel bore. A buer assembly 17 is threadably mounted to the rear end of receiver 12 and an axial hole 18 through barrel extension 16 provides communication between the bore of barrel 14 and the inside of receiver 12.

A cartridge magazine 20 is releasably mounted to the underside of receiver 12 so as to extend vertically upward thereinto through an accommodating port 22. Such magazine is of box type construction and is provided with a pair of opposing lip portions 24 for releasably retaining a stack of cartridges 26 therein. Such lip portions are formed by the upper portions of the sides being bent arcuately inward with suiiicient clearances being provided between the lip portions and in the ends `of the magazine for the sliding removal of the cartridges 26 from the magazine by a bolt assembly 28 as hereinafter described.

Bolt assembly 28 is mounted within receiver 12 for sliding reciprocation between a battery and a recoil position and functions as hereinafter described to ram a cartridge 26 from magazine 20 into the bore of barrel 14 during movement to battery position and to extract the fired cartridge case from the barrel and eject it upwardly out of an ejection port 30 in the receiver during movement to the recoil position. Bolt assembly 28 includes a carrier 36 which is engageable by a conventional gas actuated operating rod 32 to energize the bolt assembly for cyclic operation and directly actuates the bolt assembly to the rearward position. A pair of compressible springs 33 symmetrically disposed in receiver 12 are disposed between buffer assembly 17 and carrier 36 for returning bolt assembly 28 to battery position.

Bolt assembly 28 includes a bolt 34 which, like carrier 36, is cylindrical in conguration. A segmental portion is removed from the bottom of carrier 36 along the length thereof and recesses 40 extending upwardly from such segmental portion and are spaced so as to slidingly receive therebetween the lip portions 24 when such carrier passes over magazine Ztl. Diametrically-opposed rails 42 extend outwardly from carrier 36 along the lateral axis thereof to be slidably received by mating tracks 44 provided longitudinally along the inside of receiver 12 for restraining such carrier against rotation.

A bore 46 is provided axially through carrier 36 t0 slidingly receive bolt 34 and communication is made with Such bore from the underside of carrier 36 by means of a mouth portion 48 which is formed between a pair of laterally spaced and vertically disposed sides 50.

Bolt 34 includes a body 52, a head member 54 and a striker extension 56, all of which are cylindrical in configuration and have approximately the same radii. Bayonet .lugs .58 are disposed on the-.front end of body 52 :for cooperation with corresponding Vbayonet lugs P60 in hole 18 of barrel extension 16 whereby bolt 34 is releas ablylocked against longitudinal displacement when -such body .portion is rotated 90 Ifrom normal position, as

hereinafter described, after the bolt reaches .battery position. Head .member 54 and striker extension56 are'coaxially mounted respectively to the front and rear. -ends of body S2 to permit rotational movement of such body relative to such head member and striker .extension through the cooperation of reduced diameter port-ions 62-and 64, provided respectively on such head and striker extension, with cooperating holes 66 and 68 formed re- Vspectively inthe ends of such-body.v A lug 70 extends radially from'reduced diameter portion 62forrcoopera tion with an L-groove 72 provided inhole 66 so as to be entered yfrom the front end of body 52 to releasably maintain head member 54 in -rotational engagementwith the front end of the body during rotation thereof .to and from lock position and striker extension 56 is similarly held in rotational engagement with the rear end of body .52 but against longitudinal displacement by-means of a lug 71 and an L-groove 73. Head member 54 and .striker extension 56 are joined and held againstrotation by means of an ejector 74 which extends therebetween along the bottom of bolt 34 and is received .by mouth portion 48 for sliding engagement'withthe ksides- 50. The .front end of ejector 74 is joined to head member 54 by dovetailed means 76 and the rear end .is joinedto striker extension 56 through T-slot means 78 (Fig. 10) whereby through the sliding engagement of the ejector with Vthe sides 50, such head member and strikerextenvsion are restrained Ifrom rotational displacement while body 52 is free to be rotated to and from-lock .position. Such rotation of body 52 between lock and-unlock positions is produced through the cooperation yof a roller mounted cam follower 80, to be furtherdescribedhereinafter, with a cam slot 82 provided in bore 46. whereby bolt 34 is rotated approximately 90 in a clockwise direction to the lock position when ycarrier 36 moves over such bolt.

A lock 83 is mounted in carried'36 for radial reciprocation between a latch Iand an unlatch position. When lock 83 is in the latch position the inner end thereof is which leaves a corresponding portion 92 on the front end of body 52 which is uncovered by such head. Extending forwardly from front wall 86 is a well 94 which slidingly receives a plunger 96 which is extendable into engagement with portion 92 of body 52. A coil spring 98 is disposed in well 94betwe'en the front end thereof and plunger 96 to press such plunger against body 52 and, consequently, bias ejector 74 forwardly. The forward movement of ejector 74 is limited by the engage- 'ment of rearwall88 lwith the bayonet lugs 58 which, except when body 52 is in locked position, lie approximately in the.vertical axis ofthe rearm. However,

- when the lugs 58 Iare laterally disposed in lock position,

which places them out of engagement with rear wall 88, v

the front end `of ejector 74 is pressed againstthebase of the chambered cartridge 26, as hereinafter explained, and thereby is held against forward displacement. -Rearv ward movement of ejector 74 is .limited by `the.engage in engagement with a chordal at 8S longitudinally disposed on the outside of striker extension 56. Flat 85 is disposed so as to be in registry with lock 83 when bolt 34 is in the yforward position thereof in the kcarrier so that when the lock is in the latch position the bolt and oarrier are releasably connected for travel Vtogether in extended relationship through the engagement of cooperating cam surfaces 89 and 91 provided respectively on the inner end of the lock and at the front end of flat 85. The forward pressure of cam surface 91 against cam surface 89 biases lock 83 outwardly to the unlatch position but such lock is held in the latch position until bolt 34 reaches battery position by the sliding engagement of the outer end thereof with the inside of receiver 12. When bolt 34 is in battery position, the outer end of lock 83 is in registry with an elongated channel 87 in the yinside of receiver 12 whereby the latch is moved to theunlatch position through the cooperation of the forward bias of carrier 36 by the spring 33 with the cam surfaces 89 and 91 to disconnect the bolt from the carrier which may proceed forwardly until stopped 'by engagement with the rear end of barrel extensionV 16. A clearance 84 is provided'at the front end of ejector 74 to rotatably receive the bayonet lugs 58 when body 52 is lrotated and such clearance is terminated by `a liront wall 86 and a rear wall 88.

Formed on the bottom of head S4 by .the vpart of the dovetailed means 76 therein iis a 'segmental relief vcut 90 ment of front wall 86 with portion A92 of body '52.' l The front end of ejector 74 is contactable with 'the base of the top .one of the cartridges 26 in magazine 20 during movement of bolt34 to battery position for ramming such cartridge from the magazine into barrel 14. The bottom of ejector 74 is convex-shaped to present a smooth surface to the remaining stack of cartridges 26 in magazine 20 during reciprocal travel ofbolt 34.Y The front end of ejector 74 .is beveledto form a ramp portion 100 extending rearwardly and downwardly from the front end of the ejector 'and acam portion 102 extending upwardly and rearwardly from the front endof such ramp. portion. Ramp portion 100 allows ejector .74 to ride over the remaining stack of cartridges 26. in maga- Zine 20 by camming the stack downwardly so that the ejector may slide thereover while .cam portion 10,2 vserves to support the red cartridge case while being extracted and to propel .the tired case upwardly by the camming engagement of such cam surface with the rimof the case when ejector 74. is. moved forwardly. Such .forward movement of vejector 74 is produced by the engagement ofthe rear end of the ejector, .noted at 75, with buffer assembly 17 when bolt assembly 28 reaches recoil position. Extraction ofthe fired cartridge cases .from barrel 14 and the guiding support of such cases .during ejection is provided by a pair of extractors 104 which are oppositely disposed. alongthe lateralaxis of head V54 and arc .pivotally received as hereinafter described incorresponding recesses 106. V

Each of the extractors includes a-body .portion 108 `and a -claw portion .110 which projects vfrom the outer portion of `the body portion beyond the front end .of head member 54 so as to releasably grip the extraction grooves ofthe cartridges 26.- Thefouter surfaces of body portion 108 and claw portion 110 cover the orifices of the recesses .106 to prevent debris enteringy thereinto. Extending forwardly from the front end of body portion v10.8 from lthe inner side thereof is acylindrical nub .112 which .is pivotally received in aV corresponding pocket 114 providedinthe front wall of the cooperating one Y of the recesses 106, as best shown in Fig. 9, to provide pivotal support for the extractormounted therein.- The extractors 104 are held against disassembly from .head member 54 by the engagement ofthe rear ends of.body portions 108 with the lfront end of body 52 and theouter movements of the claw portions are limited bythe engagements of the inner corners of the rear ends Vof the body portions with the front end of such body. A spring 116 is mounted between the bottom of Y each ofthe recesses 106 and the inner sides of the body portions 108 for biasing the claw portions1170 inwardly so as' to clamp the cases of the cartridges 26 firmly and uniformly therebetween. v'

A striker assembly 118 is coaxiallyV mounted "toy striker extension 56 so as to extend forwardlytherefrom and is slidingly received by suitable holes bored `vaxially through body 52 and head .member 54. Such striker vassembly includes a tiring pin 120 provided with a body portion 122 which is termina-ted at the rear end by an annular ange 124 and at the front end by a reduced diameter striker portion 126 which is contactable with a chambered cartridge for discharge thereof when bolt 34 is in battery position. Firing pin 120 is slidingly mounted to striker extension 56 by means of an axial hole 128 which is counterbored to receive body portion 122 and flange 124 and to form an annular shoulder 130 which is engageable by the front end of such flange to establish the tiring position of the firing pin. A lock pin 132 extends diametrically through the forward portion of flange 124 to form projecting ends 134 which are slidingly received by elongated slots 136 in striker extension 56 so as to permit longitudinal movement of ring pin 120 between the firing and cocked positions. A roller 138 is rotatably mounted on each of the ends 134 and the slots 136 are so disposed instrliker extension 56 that, when firing pin 120 is in the cocked position, the rollers are retracted within the larger diameter portion of such striker extension and thereby permit rotation of body 52.

Firing pin 120 is biased forwardly to firing position by a compressible spring 140 which is assembled over body portion 122. Such spring is engaged at the front end by a seat 142 which is releasably mounted to the front end of body portion 122 and at the rear end by a sleeve 144 slidingly mounted on body portion 122 forwardly of striker extension 56. As best shown in Fig. 8, sleeve 144 is anchored to bolt 34 by means of cam follower 80 which is provided with a rectangular portion 146 which is slidingly received by a mating rectangular opening through body 52 of the bolt and is bifurcated to form a pair of tines 14S which are matingly received by diametrically opposed segmental recesses 150 in sleeve 144 whereby such sleeve is restrained from longitudinal displacement relative to the bolt, A shaft 152 extends axially from the outer end of rectangular portion 146 for rotatably mounting a roller 154 which is slidably received by cam slot 82 for rotating body 52 through relative movement between bolt 34 and carrier 36. Cam follower 80 is installed through a corresponding opening 155 through carrier 36.

Firing pin 120 is retracted to the cocked position through the cooperation of the rollers 138 with a pair of cam recesses 156 provided in the rear end of body 52. Each of the recesses 156 is substantially right triangular in configuration and is provided with a cam surface 158 which extends angularly forward and in a clockwise direction from the rear end of body 52 so as to cammingly retract such striker extension when body 52 is rotated to lock position. When body 52 is in lock position, sutiicient clearance is provided by the recesses 156 to permit forward movement of the rollers 13S when tiring pin 120 is released to go to ring position. A suitable sear device7 such as is shown by 160, is mounted in striker extension 56 for releasably holding firing pin 120 in t'ne cocked position.

Shown in Figs. 13-16 is an alternate device for ejecting tired cartridge cases from the firearm. In such device, a slide 162 is mounted for sliding vertical movement in a recess 164 provided therefor in the front end of head member 54 through the cooperation of tongue portions 166 extending along the sides of such slide with mating grooves 16d provided in the sides of such recess. A spring loaded plunger 170 is mounted in a corresponding aperture 172 in slide 162 so as to extend upwardly to engage the top side of recess 164 for biasing slide 162 downwardly. The downward movement of slide 162 is limited by the engagement of the bottom ends of the tongue portions 166 with the ends of the grooves 168. An orice 174 permits extension of striker portion 126 through slide 162 to re the chambered cartridge when the slide is in the down position. Extending forwardly from the bottom end of slide 162 is a lip portion 176 which is arcuately shaped to uniformly engage the bottom portion of the rim of the fired cartridge case carried by the extractors -104 for sliding the fired case upwardly from under the claw portions and out ejection port 30 when the slide is actuated upwardly in recess 164. Such upward movement of slide 162 is produced by the engagement of a cam portion 177 on an ejector 179, which is otherwise similar to ejector 74, with an angular portion 178 which extends upwardly and rearwardly from the bottom of such slide when the rear end of such ejector strikes buffer assembly 17.

Operation The bolt mechanism of the present selected embodiment operates as follows: The lfirearm is charged and ready to lire when a cartridge 26 is chambered in barrel 14, bolt 34 is locked in battery position and firing pin is releasably held in cocked position by sear 160'. To fire the firearm, sear is actuated to release tiring pin 120 by a suitable ring mechanism shown schematically at 130. Upon discharge of the cartridge, the resulting gas pressure actuates operating rod 32 against carrier 36 which is energized thereby for rearward travel in receiver 12. During the initial portion of such rearward travel, bolt 34 is restrained from longitudinal movement through the engagement of bayonet lugs 58 thereon with the corresponding bayonet lugs 60 in barrel eX- tension 16 and thereby cam slot 82 is moved relative to. cam follower 80 to rotate body 52 to disengage the bayonet lugs 58 from lugs 60 so that when such cam follower engages the front end of the cam slot, to transfer rearward movement of the carrier to the bolt, such bolt is free for rearward travel. of body 52 to unlock position, the cam surfaces 158 are actuated against the rollers 13S to retract firing pin 120 to cocked position for latching by sear 160, and during the following cyclic travel of bolt assembly 28, the firing pin is prevented from being accidentally released because of the engagement of the rollers with the rear end of body 52.

When bolt 34 is moved rearwardly, the pair of extractors 104 remove the red cartridge case from barrel 14 with a uniform force and through the support of cam portion 102 of ejector 74 the case is kept central of the front face of the bolt and longitudinally disposed to prevent contact with the stack of cartridges in maga- Zine 20. When bolt 34 reaches recoil position, the rear end of ejector 74 engages buffer assembly 17 and thereby is propelled forwardly to move cam portion 102 against the rim of the fired cartridge case, causing such case to be ejected out of the receiver through ejection port 30.

Bolt assembly 28 is immediately actuated from recoil to battery position through the energy impressed iny springs 33 during the recoil movement and during such forward travel, the front end of ejector 74 engages the base of the top one of the cartridges 26 in magazine 20 and causes such cartridge to be pushed into the chamber of barrel 1'4. Cartridge 26 is prevented from being thrown into the chamber ahead of bolt 34 through the resiliency given to ejector 74 by spring-biased plunger 96, which serves to cushion the shock of the pickup. This cushioned pickup also helps to prevent orientation of the propellant powder in cartridge 26 and thereby provides for uniform ignition. Just before bolt 34 reaches battery position, the front end of ejector 74 engages the end of barrel 14 and thereby helps to decelerate the bolt. Further deceleration is provided by the extractors 104 which are forced to pivot outwardly against the bias of the springs 116 by the engagement of the forward ends of the claw portion 110 with the rim of cartridge 26 before'engaging the extractor groove.

Also, just before bolt 34 reaches battery position, lock 83' is actuated to unlock carrier 36 from the bolt, permitting the carrier .to continue forwardly to rotate body 52 so that the bayonet lugs 58 thereon are engaged With' During such rotation the -cooperating'lugs 60 in barrel extension 16 and thereby lock bolt 34 against rearward displacement. Such rotation, too, rotates the cam recesses 156 to provide clearance for the forward movement of ring pin 120 to Ifiring position when sear 160- is actuated.

The disassembly of bolt 28 is easily accomplished without tools as follows: First, buffer assembly 17 is uns'crewed from the rear end of receiver 12 freeing the springs 33 which are removed whereupon Vbolt assembly 28 may be slid out of the receiver after bolt 3'4 is rotated -to unlock position by a conventional charger mechanism (not shown) which is attached to the bolt assembly to provide means for manual actuation thereof. Next, bolt 34v is moved in carrier 36 until cam follower 80 aligns with opening 155 whereupon the cam follower may be easily removed by turning bolt assembly 28 Vvuntil such opening faces in a downward position and tapping carrier 36. With cam follower 80 removed, bolt 3'4 is removed as a unit from carrier 36 through the cooperation of ejector 74 and may be disassembledv by rotating body 52 until the

lugs

70 and 71 are aligned with the egresses of the L-shaped grooves 72 and 73, respectively, whereby head v514 and striker extension 56 may be slid out of engagement of such body and ejector by means of the dovetailed means 76 and T-slot means 78, respectively. With head member 54 removed, extractors 104 are released for easy removal and striker assembly 1'18 is removable from striker extension 56 by the sliding removal of locking pin 132 and the detachment of seat 142 from firing pin 120 permits removal of spring 140 and sleeve 144 to complete the disassembly.

From the foregoing it is readily seen that the bolt assembly of this invention is easily removed from the firearm and disassembled. It is also apparent that the operating forces are symmetrically distributed to eliminate as much as possible any vibrations produced by unbalanced forces and movement, which would affect accuracy of the firearm, through the receiver, barrel, bolt and striker assembly being coaxially mounted together. Further, through the employment of dual extractors symmetrically mounted to the bolt, a uniform force is produced between the cartridge and bolt during the chambering and extracting operations and many of the moving parts are roller mounted to eliminate frictional resistance and adverse forces.

Other advantages of the bolt assembly of the present invention are, that while the bolt employs the preferred rotating means for locking, the head and striker portions thereof are nonrotatable, because of the cooperation of the ejector therewith, and this eliminates the frictional engagement between the bolt and engaged cartridge during chambering and extracting and application of torque to the cartridge. Also, through the cooperation of the-ejector with the dual extractors the fired cartridge case is ejectedfrom the firearm uniformly and 'without spinning as the case is slid out from under the extractor claw rather ythan rotated out as with conventional bolts which employ a single extractor.

Although a particular embodiment of the invention has been described in detail herein, it is evident that many variations may be `devised within the sp-irit and' scope thereof and the following claims are intended to include such variations.

il claim:

l. For a firearm provided with a tubular receiver, a buffer assembly for inclosing the rear end of the receiver, a cartridge magazine extending upwardly into the receiver and a barrel with an attached barrel extension mounted to the front end of the receiver, a bolt assembly includying a cylindrical carrier slidingly mounted in the receiver for reciprocation between a battery and a recoil position yand provided Vwith an axial hole therethrough and a mouth portion providing communication with said hole from the underside of said' carrier, a bolt slidingly received bylsail .holeandcincluding a body, a head member axially mounted to the front end of said body to permit Yrotation without linear displacement of said body relative to said head, afstriker extension axially mounted to the rear end of said body to permit rotation without linear displacement of said bodyrelative to said striker extension, an ejector slidingly received by said mouth portion, T-slot` means for mounting said ejector to said striker extension and dovetail means for slidingly mounting said ejector to said head member for sliding longitudinal movement and for engagement 'with the top one of the cartridges in the magazine for chambering in the barrel, resilient means disposed between said body and said ejector for biasing said ejector to a normal forward position and for cushioning. the engagement of the front end of said ejector with the top one of the cartridges in the magazine, locking means on said body cooperable with corresponding locking means provided in the barrel extension for locking said bolt in battery position when said body is rotated, a cam follower extending radially from said body Afor sliding cooperation with a cam slot in said carrier for rotating said body to lock and unlock said bolt during relative movement between said bolt and' said carrier, a pair of yextractors pivotally mounted to said head member symmetrical to said ejector forruniformly extracting tired cartridge cases from the barrel and for slidingly supporting the fired cartridge cases during ejection, a rear end on said ejector engageable with the buffer assembly when said bolt assembly is in recoil position for moving said ejector forwardly, and a cam portion on the front end of s aid ejector engageable with the rim of the red cartridge case gripped by said extractors for ejecting the fired cartridge case from the firearm when said ejector is moved forwardly.

2. For a firearm provided with a tubular receiver, a buffer assembly for inclosing the rear end of the receiver, a cartridge magazine extending upwardly into the receiver and a barrel lwith an attached barrel extension mounted' to the front end of the receiver, a bolt assembly including a cylindrical carrier slidingly mounted in the receiver for reciprocation between a battery and a recoil position and provided with an axial hole therethrough and a mouth Vportion providing communication with said hole from the underside of said' carrier, a bolt slidingly received bysaid hole and including a body, a head member axially mounted to the front end of said body to permit rotation without linear displacement of Said body relative to said head, a striker extension axially mounted to the rear end of said body to permit rotation without linear displacement of said body relative to said striker extension, an ejector slidingly received by said mouth portion, T-slot means for mounting said ejector to said striker extension and dovetail means for slidingly mounting said ejector to said head member for sliding longitudinal movement and for enga-gement with the top one of the cartridges in the magazine for chambering in the barrel, resilient means 'disposed between said body and said ejector for biasing said ejector to a normal forward position and for cushioningV the engagement of the front end of said ejector with the top one of the cartridges in the magazine, locking means on said body cooperablewith corresponding locking means provided in the barrel extension for locking said bolt in battery position when said body is rotated, a cam follower extending radially from said body for sliding cooperation vwith a cam slot in said carrier for rotating said body to lock and unlock said bolt during relative movement between said bolt and' said carrier, a pair of extractors pivotally mounted to said head member symmetrical to said ejector for uniformly extracting fired cartridge cases from the barrel and for slidingly supporting the fired cartridge cases during ejection, a rear end on said ejector engageable with the buffer assembly when said bolt assembly is in recoil position for moving said ejector forwardly, a 'slide mounted for sliding vertical movement between an up and a down position in a centrally ldisposed recess provided therefor in the front face of said head member, a spring-pressed plunger for biasing said slide to the down position, a lip portion extending forwardly from the bottom of said slide for engagement with the cartridge case held by said extractors, and cooperating cam surfaces on said slide and said ejector for moving said slide to the up position and propelling the cartridge case from behind said eXtractors and out of the irearm when said rear end engages said buffer assembly.

3. A rearm including a receiver with a magazine mounted thereto for delivering a supply of cartridges therein into said receiver, a barrel with an attached barrel extension mounted to said receiver, a bolt assembly slidingly disposed in said receiver for successively transferring the cartridges from said magazine to said barrel during movement of said bolt assembly to a battery pesition, said bolt assembly including a carrier mounted for translational reciprocation in said receiver and a cylindrical bolt axially mounted therein for sliding movement relative thereto, said bolt including a head member and a striker extension With a body coaxially mounted therebetween for rotation respective thereto, extractor means mounted to said head member for extracting the tired cases from said barrel, cooperating locking means on said body and in said barrel extension for releasably locking said bolt in battery position when said body is rotated, an ejector for ejecting fired cases from the firearm, dovetail means for slidingly mounting the front end of said eector to said head member, T-slot means for slidingly mounting the rear end of said ejector to said striker extension whereby said body is bridged for rotation respective to said head member and said striker extension and said extension is slidable respective thereto, and a mouth portion disposed in said carrier for slidingly receiving said ejector to prevent rotation of said head member and said striker extension respective to said carrier and to position said ejector for engagement with successive ones of the cartridges in said magazine for transferral therefrom to said barrel.

References Cited in the le of this patent UNITED STATES PATENTS 798,866 Bennett et al Sept. 5, 1905 2,491,616 Clarke June 4, 1946 2,424,264 Yorks July 22, 1947 2,603,019 Elkas July 15, 1952 2,719,477 Simpson June 14, 1955 FOREIGN PATENTS 798,197 Germany July 15, 1941