US1347756A

US1347756A - Gun

Info

Publication number: US1347756A
Application number: US353704A
Authority: US
Inventors: Oscar V Payne
Original assignee: AUTO ORDNANCE CORP
Current assignee: AUTO ORDNANCE CORP; AUTO-ORDNANCE Corp
Priority date: 1920-01-24
Filing date: 1920-01-24
Publication date: 1920-07-27
Anticipated expiration: 1937-07-27
Also published as: FR521723A

Description

0. V. PAYNE.

GUN.

APPLICATION FILED JAN. 24, I920. r

' Patented July 27, 1920.

3 SHEETSSHEET 1.

0. v. PAYNE.

sun.

APPLICATION FILED JAN. 24, 1920.

Patented July 27, 1920.

3 SHEETSSHEET 2.

O. V. PAYNE.

GUN.

APPLICATION FILED JAN-24, 1920.

Patented July 27, 1-920.

3 SHEETSSHEET 3.

W V r r y UNITED STATES PATENT OFFICE.

OSCAR v. PAYNE, or cLnvELAnn, 01-110, ASSIGNOR r0 AUTO-ORDINANCE conroim- TION', on NEW YORK, n. Y., A CORPORATION on NEW YORK.

GUN.

Specification of Letters Patent.

Patented July 27, 1920.

Application filed January 24, 1920. Serial No. 353,704.

To all whom it may concern:

Be it known that I, OSCAR V. PAYNE, a citizen of the United States, and resident of Cleveland, in the 'county of Cuyahoga and State of Ohio, have invented new and useful Improvements in Guns, of which the following is a specification.

This invention relates to guns, particularly automatic guns of the smaller types such as rifles and machine guns, more particularly to guns of the type having a breech closure reciprocatable rearwardly and forwardly and rotatable into locked position at the forward end of its stroke, and still more particularly to guns operating, according to the discovery set forth in the patent, to Blish 1,131,319, granted March 9, 1915, wherein the receiver and breech closure are provided with looking abutments inclined to the line of breech pressure at such angle. that the closure is held closed during high breech pressure but is automatically unlocked directly in response to the breech pressure acting through the closure when the pressure decreases to a relatively low value.

In automatic guns of the type referred to, having a reciprocatory breech closure arranged to rotate into locked position at the forward end of its stroke, the purely reciprocatory movement of the closure durlng' its recoil must be quickly changed into a combined reciprocatory and rotary movement at the end of its forward stroke and vice versa as the closure unlocks and opens, especially in rapid fire guns where the cycle of operation is repeated many times per second. Heretofore, cams or guides have been provided on the receiver in the path of lugs on the closure, the guides extending obliquely to the line of reciprocation to throw the closure into locked position at the end of its forward stroke, other ides being provided to stop the rotation 1n unlocking and to guide the closure in its recoil movement. With such an arrangement a sharp impact results eachtirne the lugs strike the oblique cams or guides at the forward end of the stroke and a still sharper impact results each time the lugs strike the longitudinal guidesin the unlocking rotation of the closure. These. impacts cause excessive wear and frequent breakages and mitigate against accurate firing.

Another difliculty encountered in us of the aforesaid type is that of forming the locking abutments on the boltand more especially in the receiver, and of making these abutments of sufficient strength to Withstand the wear and tear of the breech pressures, these pressures rising to the order of fifty thousand pounds per square inch in military rifles for example. v

Furth rmore it is essential that the weight of, military firearms and other portable guns be minimized to the greatest possible extent. Moreover, in guns of the aforesaid type 1t is desirable to have one or more lugs or projections extend'outwardly from the breech mechanism through slots in the receiver to control the breech mechanism, and in order to exclude dust and other foreign matter it is essential that these slots be closed. I Another difficulty experienced in guns of the type referred to is that of securing uniform and reliable action. While known guns of this type will function well at times, they frequently function erratically or not at all. I have discovered that this difiiculty can be overcome by uniformly lubricating the contacting surfaces between the locking abutments 'of the rebeiver and breech closure and that this lubrication does not destroy the locking qualities of the abutments at high breech pressure, as would be expected, presumably for the reason that the film of lubricant between the abutting 'surfacesis momentarily squeezed into the interstices of the abutments during the infinitesimal interval of high breech pressure.

The principal ob ects of the present invention are to overcome the aforesaid and other difiiculties and to provide the ,aforesaid and other essentials. More particular objects are, viz.: smoothly to blend the reciprocatory and rotary movements of the breech closure so as practically or wholly to eliminate the aforesaid impacts and the wear and other disadvantages incident thereto; to provide interlocking abutments on the breech closure and receiver which may be manufactured with facility and at alow cost, and which have extenslve bearing surfaces and great strength, and at the sa-me'time low weights; to provide a gun which is lighter than known of like capacities and capabilities but which is more durable and safe; to provide means for automatically closing the slots or other openings provided in the receiver for projectingparts the working mechanism of the breech action; to provide means for lubricating the,

locking abutments of the receiver and breech ,closure and other sliding parts of the mechanism so as to render the automatic action of the breech mechanism uniform and reliable and to reduce the wear; and generally to improve the' construction and operation of guns of the aforesaid types.

The inventionconsists in providing guns of the aforesaid types with an interfitting lug and guideway on the bolt and receiver respectively (or vice versa) for guiding the movements of the bolt, the guideway having a longitudinal portion and a transverse portion tangentially connecting with the longitudinal portion throughout a gradual and uninterrupted bend so that the rotation of the closure into and out of locked position blends with its reciprocation smoothly and without impact, and the lug and guideway being coordinated with the locking abutments so that the abutments are guided into and out of locking engagement throughout a smoothly curving path without subjecting the abutments to impacts or other forces. I have discovered that these results cannot be satisfactorily attained without extending said bend circumferentiallythroughout a relatively wide angle, preferably at least of the order of 40 (in a gun with two sets of locking abutments) and this angle is not available in known guns in which the total angle of bolt rotation. is only 90 or less. I therefore propose to interrelate the guiding lug and guideway with the locking abutments so that the bolt may be rotated through a much wider angle, preferably at least of the order of 110, thereby affording an angle of 40 e. g. for blending therotation into the reciprocation and a further angle of 6. g. for interengaging' the abutments. This involves a novel arrangement of the locking lugs or abutments on the bolt relative to those on the receiver whereby the two sets are angularlyspaced from each other in the unlocked position of the bolt by an angle approximately equal to the angle of said bend, that is, 40 in the example stated.

The invention also involves a shutter for closing the aforesaid slot or slots in the receiver, the shutter being nonreciprocat able but rotatable with the bolt to close the slots when the bolt is in locked posi-.

tion and having'one. or more longitudinal slots to accommodate the lugs or other parts projecting from the breech mechanism outwardly through the receiver. The shutter preferably comprises a tube fitting in the receiver tween the bolt and the inner wall of the receiver.

Another feature of the invention consists in forming the receiver into two parts, preferably tubular, fitted together end to end, and in forming said guldeway in the form of intercommunicating slots in the two parts. The forward part is provided with the locking abutments and the inclined portion of the guideway slot, and is made sufiiciently heavy to withstand the stresses set up by the breech pressure. The locking abutments are preferably formed on a cylindrical sleeve or tubular member adapted to be threaded or otherwise secured in said forward part of the receiver. The rearward part of the receiver is arranged to serve merely as a recoil housing and guide for the breech bolt and may therefore be made relatively thin and light. Indeed it is preferably formed as a thin tube of pressed metal, closed at its rearward end to confine the recoil spring and threaded at its forward end to thread into the forward part of the reoeiver'in abutting relationship with said locking sleeve. The shutter is also preferably formed as a pressed-metal tube adapted to fit within said rearward tubular part of the receiver with its forwardand rearward ends abutting respectively against said locking sleeve and said closed end of the rearward part of the receiver.

' The forward part of the receiver and said locking sleeve are provided with lubricant ducts leading to the abutting surfaces of the locking abutments, wicks or other suitable lubricant feeding means being associated with these ducts to afford a uniform lubrimanner the lubricant may be transmitted to a part or all of the sliding surfaces of the breech mechanism, in addition to the locking surfaces, by being carried along the sliding surfaces as the parts-slide back and forth or by being supplied in such quantity as to flow over the surfaces Other improvements herein disclosed, such as the firing pin, trigger mechanism, combined magazine and trigger guard, etc., are not claimed in the present application and will herein be described only in connection with the specific embodiment of the invention illustrated in the accompanying drawings, in which Figure 1 is a left elevation Fig. 2 is a top plan;

Fig. 3 is a left elevation, on a larger scale, of the forward part of the receiver;

Fig. 4 is a Vertical axial section, parts being broken away, showing the breech closure in fully retracted position;

- Fig. 5 is a horizontal axial section showing the breech closure in locked position;

Fig. 6 is a section similar to Fig. 4:, show- .ing the breech closure in locked position,

andi the firing mechanism in position ready to re;

Fig. 7 is a side elevation of the ejector;

I Fig. 8 is an end elevation of the ejector;

Fig. 9 is a side elevation of a catch;

Fig. 10 is a transverse section on line 101O of Fig. 6; Fig. 11 is a vertical axial section of a portion of the receiver, locking sleeve and bolt 10 with the bolt in locked position and with the firing pin removed;

Fig. 12 is a rear elevation. of the bolt'in locked position;

Fig. 13 is a left side elevation of the safety 15 catch in safe position;

Fig. 14 is a left side elevation of the bolt in locked position;

'Fig. '15 is a top plan of the trigger bar showing the safety catch in section in safe position;

Fig. 16 is a similar view showing the safety catch in firing position; and

Fig. 17 is a top plan of the forward end of the rearward part of the receiver.

The particular embodiment of the invention chosen for the purpose of illustration comprises in general a stock 1, a barrel 2, a

a receiver formed in forward and

rearward parts

3 and 4, a heat guard 5 surrounding the rear end of the barrel 2, the guard 5 being insulated from the receiver by suitable non-conducting material 91, and a frame member 6. The forward portion 3 of the re- 7 ceiver comprises substantially cylindrical 5 forward and rearward ends joined together by side walls 9 and 10,the forward end being threaded over the barrel and the rearward end being provided with internal threads to receive the locking sleeve 11 and the rear- 40 ward portion 4 of the receiver. A clip holder 92 is provided to facilitate loading the magazine from the top as in the Spring field rifle; An ejection opening 13 is provided on the right-hand side as shown in 5 Fig. 5. The frame member 6 is preferably formed of aluminium alloy or other light metal, and has the magazine chamber 14 and also the trigger guard 15 formed integrally therein. fThe frame member is connected to the forward part3 of the receiver by means I of screws 16 and 17, the screw 17 having an axial lubricant duct extending therethrough,

and having a "lubricant cup 18 threaded thereover.

The locking sleeve 11, which is preferably formed of, bronze, or other high pressure bearing material, is adaptedto be threaded into the part 3 of .the receiver from the rear. The locking sleeve is provided onits inner periphery with upper and lower sets '19 and 20 of locking lugs which extend radially inwardly, the lugs of each set be- 'ing disposed in aliriement longitudinally of the gun. The forward faces of these locking lugs are inclined circumferentially with respect toa plane perpendicular to the axis of the gun at such angles that the 'bolt lugs v abutting thereagainst will be locked thereto during high breech pressure but will slide thereover due to-'- the circumferential obliquity of the contacting faces when the pressure drops to relatively low value, thereby automatically unlocking the bolt according to the discovery in the aforesaid patent to Blish. Each set of

lugs

19 and 20 exin the rear end of the forward portion 3 of the receiver. Disposed in the rearward end of the tube 4 is a buffer comprising a rearward portion 23 and a forward portion 24 telescoping over the rearward portion, the space within the two portions being filled with disks 25 of leather or the like, and the two portions being connected together by a small rod 26 adapted to be compressed or flexed by impacts on the forward end of the buffer."

The two

portions

3 and 4 of the receiver are provided with

intercommunicating slots

27 and 28, the slot 28 extending longitudinally of the rearward portion 4, and the slot 27 bending circumferentially "to the right and connecting tangentially with the slot 28 as shown in Fig. 2. The inclined portion 27 of the slot bends gradually away from the longitudinal part; 28 through a circumferential angle of approximately 40 and then continues at substantially a constant angle to a plane perpendicular to'the axis of the gun through an angle of substantially 70. The forward portion 3 of the receiver is reinforced on opposite sides of the portion 27 of the slot 6 shown in Figs. 3, 4 and 6.

Rotatably fitted within the rear portion 4 of the receiver is a tubular shutter 29 abutting at its rearward end against the rear end of the tube 4 through the base of the buffer, and abutting at its forward end 120 against the rear end of the locking sleeve 11. This sleeve is provided with a longitudinal slot 30 adapted to register with the longitudinal slot 28 in the receiver when the bolt is in unlocked position. The tube 29-is also 125. provided with a longitudinal slot 31 oppo- (Fig. 6) fitting in groove 41 (Fig. 14) in the bolt. The extractor is provided with a lug 93 adapted to ride in a groove 90 in the receiver and locking sleeve, this lug serving to keep the extractor in line with the notch provided in the barrel for the forward end thereof. Extendin from the rearward end 50f the olt is an actuating. lug 37, this lug .extending outwardly through the

slots

28 and 30 in the tubes 4 and 29. Immediately in advance of the enlarged head are two sets of lugs 38 and 39 adapted to interengage with the

lugs

19 and 20 on the locking sleeve 11 when the bolt is in locked position, the abutting faces of these lugs facing rearwardly in opposition to the forwardly facing lugs on the locking sleeve. The forward end of the bolt is provided with a longitudinal slot 40 (Fig. 14) decreasing in depth from front to rear and vanishing a short distance in front of the groove 41 for the extractor, the groove 40 being adapted to receive the ejector hereinafter described. The head 35 of the bolt is provided with a rearwardly facing cam 42 extending circumferentially of the bolt through an angle of approximately 110 for the purpose of retracting the firing member in the unlocking movement of the bolt as hereinafter described.

The bolt 34 is provided with an axial chamber whose diameter decreases from the rear to the front by steps, and within this opening the firing pin 43 is arranged. both to rotate and to reciprocate relatively to the bolt. The firing pin bears directly on the bolt at the forward end, and at the rearward end it bears in a sleeve 44 threaded into the rearward end of the bolt. The firing pin is provided with a depending lug 45 adapted to extend downwardly through the slots 31 and 32 in the tubes 4 and 29, the lug 45 being provided with a beveled cam face 46 adapted to be enga ed by the cam 42 on the bolt.

i feature which I believe to be novel but which I do not claim in the present application, involves a simplified means for mounting the firing pin spring 47 on the firing pin. This means comprises a collar 48 formed integrally with the-firing member and provided with an oblique slot 49 (Fig. 6) the forward end of the firing pin spring 47 radially being contracted so as to engage behind this collar. By virtue of the oblique slot 49, the contracted end of the spring 47 may be threaded over the collar 48 from the frontin assembling the spring on the pin, the firing pin first having been inserted through the sleeve 44. After the firing pin unit is thus assembled, the sleeve 44 is threaded into the rearward end of the bolt. The breech closure is yieldingly urged forwardly by a recoil spring 50 which fits loosely within the inner tube 29 and around the buffer 24. The recoil spring is anchored to the boltat 51 and to receiver at 52, and in putting it in place it. is subjected to a torsion which tends to turn the bolt in a clockwise direction into locking position.

The ejector comprises a tubular member 53' closed at its inner end and provided with a flat nose 54 extending centrally from the closed end (Figs. 5, 7 and 8). This ejector is adapted to extend radially through an opening 55 in the left side of the forward part 3 of the receiver (Figs. 3 and 5). The opening 55 extends through the receiver in the region where the receiver changes in internal diameter, somewhat more than the rear half of the opening extending through the portion of larger internal diameter and somewhat less than the forward half extending through the portion of lesser internal diameter. The opening is extended only through the wall of larger internal diameter, thereby leaving shoulders 56 perpendicular to the axis of the opening in the portion of smaller internal diameter. The closed end of the ejector 53, on opposite sides of the nose 54, is adapted to seat against these shoulders 56 to limit the inward movement of the ejector, the nose 54 being adapted to extend through a slot 57 in the portion of smaller internal diameter. The ejector 53 is yieldingly urged inwardly by a coil spring 58 which seats at its outer end against the bottom of a recess provided in the catch 59 in radial 'alinement with the tubular ejector.

The catch 59 is secured to the receiver by means of a threaded stud 60, this stud having a smooth extension adapted to extend into an opening in the sleeve 11 to lock the sleeve in the receiver. wardly from the stud 60 is a flexible arm provided with a lug 61 adapted to seat in an opening in the receiver, the rearwardly extending arm being sufiiciently flexible to disengage the lug from the opening while Extending rearthe stud 60 is being threaded into or out of the receiver. The spring recess in the forward end of the catch '59 opens downwardly through an opening 62 in the lower side of the catch which is of substantially the same width as the diameter of the recess and which is substantially concentric with the axis of the stud 60.

In assembling the ejector and catch, the

a catch is first secured to the receiver by 66 and a disconnector 67. pivotally mounted-in a frame 6 by means of threading the stud 60 into the receiver, the catch being rotated slightly in advance (in a clockwise direction in Fig. 9) of its normal position, the ejector 53 is inserted into the opening 55, the spring 58 is seated in the axial recess of the ejector, and the catch 59 is then rotated in a counterclockwise direction into the normal'position where the ejector slidingly fits in the recess in the forward end of the catch and where the lug 61 snaps into the opening provided therefor in the receiver.

In operation, the nose of the ejector rides on the periphery of the cylindrical bolt until the slot (Fig. 14) reaches the ejector in the recoil of the bolt, whereupon the ejector nose rides down the inclined slot under the influence of spring 58 into position to eject theempty cartridge case through the ejection opening 13. As the bolt moves forwaril, the ejector rides up the inclined groove 40 to the periphery of the bolt, after which it rides on the periphery of the bolt, as the bolt continues its ,for- Ward reciprocation and then rotates into locked position.

The firing mechanism comprises a trigger 63, a trigger bar 64, a safet catch 65, a scar he trigger 63 is pin 68. The trigger bar 64 has a notch 69 (Figs. 15 and 16) at its .rearward 'end adapted to receive the trigger and the trigger bar is yieldingly urged rearwardly bymeans of coil spring 69 abutting against'a' transverse 'web 70 of the frame 6 at its forward end and abutting the triggerbar at; its rearward;

end (Fig. 16').-

he trigger'bar 64 is fitted loosely through an opening in the trans- 'verse web 70 of the -frame6 so that it may be inserted therein after-the triggerhas been assembled and so that it may upwardly end after insertion, a spring 71 being provided yieldingly to urgeit upwardly. The sear 66 is formed as a bell crank pivoted on the'transverse pin 72 which is journaled at its opposite ends in depending lugs 75 (Fig. 3) on the receiver. The scar is normally urged in a counterclockwise direction by the sear spring 7 3 which seats on theupper end of the safety catch 65. In the normal position shown in the drawings, adapted to engage the depending the firing'member to retain the ber in retracted position. The disconnector lug of 67 comprises a pin extending through a and locking sleeve. pin is rounded and engages a peripheral cam the hooked upper end of e moved and downwardly at its forward,

' being cut into the sear is The upper end of this.

74 (Figs. 10 and 12) on the bolt, and

adapted to engage the receiver and prevent the pin from sliding too far intov the receiver chamber when the gun is inverted while the bolt is removed, and from bein lost through the sear during mounting and dismounting. 1 A

The safety catch (Figs. 4, 6, 13, 15 and 16) comprises a cylindrical portion 75 surmounted by a flange 76 adapted to rest on the upper surface of the frame 6. The catch is provided with a flat narrowed portion 77 extendin downwardly through the frame member y means of which the catch may be rotated, and with lugs 78 on the flange 76 engaging in notches in the frame to maintain it in safe and ready positions. The

cylindrical portion 75 is provided with a transverse opening to receive the trigger bar 64, and to limit its rotation, and the trigger bar is provided with a notch (Figs. 15 and 16). to hook over a shoulder of the catch whenthe catch is in'the safe position shown in Fig. 15. The safety catch is also vent the sear from being moved into firing position due to jarring the gun. Thus, the safety catch operates on both the trigger bar and the sear, thereby affording a double precaution against accidental firing.

The means for lubricating the abutting surfaces between the locking lugs has been omitted in part in Figs. 4, 5 and 6 for the purpose of: clearness,

and the omitted parts.

provided with an upwardly extendinglug 79 adapted to underlie the rear end of the 'sear in the safe position of the catch to preare illustrated in Fig. 11. These parts comprise an annular duct 85 extending around.

two ducts 81- and 82 which extend, almost to the rear of the locking sleeve, .the se ducts the outer periphery of the locking sleeve 11. Extending obliquely inwardly and forwardly from the ducts 81 and '82 are branch ducts 83 and 84 which leadto theab'utting surfaces of the locking Thus lubricant may flow from the lu ricant cup 18 through theaxial duct 80 in screw 17 to the annular duct 85,- thence rearwardly along the ducts 81 and 82, and

ring memthence inwardlythrough ducts 83 and 84 to the abutting surfaces.

The preferredmeans for assembling the parts is as follows: In assembling the frame group the trigger is secured in the frame, the safety catch 65 is inserted into position in the frame 6 from the top, the disconnector spring 71 is inserted into its recess a hooking the forward end of the recoil spring into the rear end of the bolt, turning the. tube to the right relatively to the bolt to from the top, the spring 69 is placed on the trigger bar, the triggerbar is inserted into the opening in the web 70 from the rear and thence through the safety catch 65, and

' the rear end of the trigger bar is then 'interengaged with the trigger.

as above described, and then mounting the sear on the depending lugs 75 by means of the pin 72. The frame and receiver groups are attached to the stock by means of the screws 16 and 17," and the lubricant cup 18 is then threaded over the screw 17.

The bolt unit is assembled by slipping the sleeve 44 over the firing pin from the front, slipping the spring 47 over the. firing -pin from the front and threading the constricted end of the spring over the collar 48, sliding the sleeve" forwardly. on the firing pin against the actionof spring 47 and turning the sleeve to catch. over the downwardly projecting lug on the firing pin, inserting the firing pin unitinto the bolt from the I .rear and screwing the sleeve 44 into the bolt,

and then uncatching the firing pin from the rear face of the sleeve 44 and permitting it to jump forward under the action of the spring 47, the lug 45 moving in'a longitu dinal slot on the lower side of the sleeve as shown in Fig. 6.

The recoil unit is assembled by mounting the buffer in the rear end of the recoil tube 4, slipping the shutter 29 into the recoil tube, inserting the recoil spring into the shutter, hooking the-rear end of the recoil spring into the rear end of the recoil tube,

twist the spring, then retracting. the bolt into the recoil tube with the actuator 7 sliding down the slot 28 and hooking the actuator over the shoulder provided at the rearward end of the slot 28 as shown in Fig. 2.

V The bolt and recoil units, thus assembled together, are'then inserted into the receiver from the rear, with the interrupted threads on the tube 4 (Fig. 17) clearing the interrupted threads ,at the rearward end of the part 3 of the receiver, and then turning the recoil tube to the right one-eighth turn to interengage the aforesaid interrupted threads,-the stud 61 of the catch 59 locking thetwo parts of the receiver against rota- 'The operation is as parts inthe position shownin Figs. 5 and 6, the gun is ready to fire. Upon pulling the trigger, the trigger bar 64 rocks the sear 66 in a clockwise direction until the lug 45 of, the firing pin is -disengaged by the sear,

. engagement.

follows: With a..."

I whereupon the firing pin is shot forwardly the actuator lug 37 may move freely along this oblique slot 27. After the bolt has rotated sufliciently to clear the locking lugs from each other the actuatorv lug 37 reaches the bend' in the slot 27, and in the continued rotation ,of. the bolt the movement of the lug 27 along this bend gradually blends the rotary movement of the bolt into the purely reciprocatory movement acquired when the lug 37 reaches the longitudinal slot 28. In the unlocking rotation of the bolt, the cam 42 on the rear end of the bolt engages the beveled face 46 on the firing pin lug and retracts the firing pin, the firing pin being held retracted by the cam 42 during the recoil of the bolt. When the bolt again reaches forward position the firing. pin lug 45 engages behind the sear 66 before the cam 42 disengages the firing pin in the lock ingrotation of the bolt. The firing pin is prevented from rotating with the bolt by the lug 45 extending through the slot 32in the receiver. In the locking movement of the bolt the firing pin lug 45 is 'accom-; modated by recess 33' extending in a counterclockwise direction from the slot 31. The tubular shutter '29 is caused to rotate with the bolt by the actuator-lug 37 extending through the rectilinear slot 30.

and rotary motion of the bolt does not bring the lugs on the bolt and receiver into However, when the lug 37 reaches thefioblique portion 27 of the slot 27 which portionhas substantially the same obliquity as the abutting faces of the looking lugs, the locking lugs of" the bolt are carriedinto engagement with the locking. lugs on the receiver.

In the unlocking movement of the bolt, the cam 74 (Figs. 10 and 12) moves the disconnector 67 downwardly, and the disconnector in turnmoves the-trigger bar 64 downwardly below the. seafiso that the sear is released Whether or not'the trigger is released.

According to the present invention extensive locking surfaces between the bolt and receiver are provi ed, and at the same time the weight and size of the parts are kept within low limits. The bolt stroke and consequently the receiver are short and the weights are well to the rear. By dividing the receiver into two parts and interrelating the parts in the manner described, the 1 major portion of the receiver maybe made v very light, thereby greatly reducing "the total weight of the gun. By constructing and arranging the frame 6 as described, :it serves to form both the magazine and the trigger guard and also asupport for the firing mechanism. I

I claim 1, A

gun comprising a. receiver, a breechclosure movably disposed in the receiver to reciprocate rearwardly and forwardly and to rotate, at the forward end of its stroke into locked position, the receiver and closure having locking abutments arranged to interengage when the closure rotates into locked position, and having an interfitting lug and guideway to guide the closure, the locking abutments being inclined to the line of breech pressure at suchangles as to hold the bolt closed at high breech pressure and to slide relatively to each other when the pressure drops to a low vvalue automatically to unlock the closure, the guideway having a longitudinal portion and a transverse portion tangentially connecting with the longitudinal portion throughout a gradual and uninterrupted bend so that the rotation of the closure into and out of locked position blends with its reciprocation smoothlyand without impact, andthe lug and guideway being coordinated with the locking abut-' ments so that the abutgnents are guided into and out of locking engagement throughout a smoothly curving. path.

2. A gun comprising a receiver, abreech closure movably disposed in the receiver to reciprocate rearwardly and forwardly and to rotate at the forward end of its stroke into locked, position, the receiver and closure having locking abutments arranged tointerenga e when the closure rotates into locked position and having an interfitting lug and guideway to guide the closure, the locking abutments being inclined to the line ofbreech pressure at such angles as to hold the bolt closed at high breech pressure and to slide relatively to each other when the pressure drops to a low value automatically to unlock the closure, the guideway having a Longitudinal portion and a transverse portion tangentially connecting with the longitudinal portion throughout a gradual and uninterrupted bend so that the rotationof the closure into and out of locked positlon blends with its reciprocation smoothly and without impact, and'said lug and guideway being interrelated with said abutments so.

that the bolt may be rotated through an angle at least of the order of 110.

. 3. A gun comprising a receiver, a breech closure movably disposed in the receiver to reciprocate rearwardly and forwardly and to rotate at the forward end of its stroke into locked position, the receiver and closure having locking abutments arranged to interengage when the closure rotates into-locked position and having an interfitting lug and guideway to guide the closure, the locking abutments being inclined to the 'line of breech pressure at such angles as to hold the bolt closed at high breech pressure and to so. i slide relatively to'each other when the-pres; sure drops to a low value automatically to to rotate at the forward-end of .its stroke into locked position, the receiver and clossure having locking abutments arranged to interengage when the closure rotates into locked position and having an interfitting lug-and guideway to guide the closure, the

locking abutments being inclined to the line of breech pressure at such angles as to hold the bolt closed at high breech pressure and to slide-relatively to each other when-the pressure drops to a low value automatically to unlock the closure, the guideway having a longitudinal portion and an oblique portion joined together by a gradual and uninterrupted bend so that the rotatio n of the 010-,

sure into and out of locked position blends with its reciprocation smoothly and with-' out impact, said lug and guideway being interrelated with said locking. abutments so that said bend and oblique portion extend circumferentially through angles at least of v the order of 40 and 70 respectively.

5. A ,gun comprising a receiver, a bolt adapted both to reciprocate and to rotate in the receiver, locking lugson the receiver and bolt adapted to interengage when the bolt is rotated in one direction and to disengage when the bolt is rotated in the other direction, the engaging faces of said lugs being inclined to the line of breech pressure at such angle as to look the bolt closed at high breech pressure,and to slide relatively to each other when thepressure drops to a low value automatically to unlockthe bolt, "and an interfitting'guiding lug and guideway on the bolt and receiver respec- -'tively, the guideway having a longitudinal portion and an oblique portion inclined to theline of breech pressure substantially at said angle, so as to guide the bolt in its reciprocation and to rotate the bolt at the end of its forward stroke to interengage said locking lugs, said longitudinal and oblique portions being joined by a gradual bend extending through a wide circumfer- I ential angle so as smoothly to blend the reciprocatory and rotary movements of the bolt, and the locking lugs being circumferentially separated from each other in the unlocked position of. the bolt by a wide angle so as to clear each other'during said blending.

6. A gun comprising a receiver, a bolt adapted to reciprocate rearwardly and for wardly in the receiver and'to rotate into locked position at the forward end of its stroke, the receiver having a slot extending longitudinally of the gun throughout its rearward portion and inclining circumferentially at its forward end, a lug on the bolt adapted to slide in said slot to guide the bolt in its reciprocatory and rotaryadapted to slide in said slot to guide thebolt in its reciprocatory and rotary movement, and a shutter non-reciprocatable but rotatable with the bolt to close said slot, said shutter having a longitudinal slot to accommodate said lug.

8. A gun comprislng a receiver, a bolt adapted to reciprocate rearwardly and forwardly in the receiver and to rotate into locked position at the forward end of its stroke, the receiver having a slot extending longitudinally of the gun throughout its rearward portion and inclining circumferentially at its forward end, a lug on the bolt adapted to slide in said slot to guide the bolt in its reciprocatory and rotary movement, and a tubular shutter fitting between saidbolt'and said receiver for cover ing said slot, said shutter having a longi- .tudinal slot to accommodate said lug.

9. A gun comprising a receiver, a bolt adapted to reciprocate rearwardly and forwardly in the receiver and to rotate into locked position at the forward' end of its stroke, a firing member adapted to reciprocate with the bolt, the receiver having a bolt slot extending longitudinally of the gun throughout its rearward portion and inclin- -wardly in .the receiver and to rotate into locked position atthe forward end f its stroke, a firing member adapted to reciprocate with the bolt, the receiver having. a bolt slot extending longitudinally of the gun throughout its rearward portion and inclining circumferentially at its forward end, a

I lug on the bolt adapted to slidein said slot to guide the bolt in its reciprocatory and rotary movement, said receiver also having a firing member slot extending longitudinally'thereof, a lug on the firing member extending through said last slot, and a tubular shutter fittingbetween said bolt and receiver for closing both of said slots when the bolt is in locked position, said shutter having slots to accommodate said lugs.

11. A gun comprising a receiver, a bolt adapted to reciprocate rearwardly and forwardly in the receiver and to rotate into locked position at the forward end of its stroke, a firing member adapted to reciprocate but not rotate with the bolt, the receiver having a bolt slot extending longitudinally of the gun throughout itsrearward portion and inclining circumferentially at its forward end, a lug on the bolt adapted to slide in said slot to guide the bolt in its reciprocatory and rotary movement, said receiver also having a firing member slot extending longi-. tudinally thereof, a lug on the firing member extending through said last slot, and a shutter arranged to rotate but not reciprocate with said bolt for closing both of said slots when the bolt is in locked position, said shutter having slots arranged 'to register with said receiver slots when the bolt is unlocked to accommodate said lugs.

12. A gun comprising a receiver, a bolt adapted to reciprocate rearwardly andforwardly in the receiver and to rotate into locked position at the forward end of its stroke, a firing member arranged .to reciprocate but not rotate with the bolt, the re ceiver having a bolt slot extending longitudinally of the gunthroughout its rearward portion and inclining circumferentially at its forward end, a lug on the bolt adapted to slide in said slot to guide the bolt in its reciprocatory and rotary movement, said re- .ceiver also having a firing member slot exslot, and a tubular shutter fitting between. said bolt and receiver for closing said slots when the bolt is in locked position, said shutter being rotatable but non-reciprocatable with said bolt and having slots for said lugs arranged to register with said receiver slots when the bolt is unlocked, the shutter slot for the firing member lug having an offset portion to permit rotation of the shutter with the bolt into locked position.

13. A gun comprising a receiver, a bolt adapted to reciprocate rearwardly and forwardly in the receiver and to rotate into locked position at the end of its forward stroke, said bolt having a lug to guide its movements, the forward portion of said re-, ceiver connecting with the barrel of the gun and the rearward portion comprising a tube threaded 'to the forward portion, said portions having intercommunicating slots to guide said lug, and a second tube rotatable within said first tube for closing said slots when the bolt is in locked position, said tube having a slot for said lug adapted to register with said slot when the bolt is unlocked, said second tube abutting at its forward end against the rearward endof the forward portion of the receiver and against the rearwagd end of said first tube at its rearward en 14. A gun comprising a receiver, a bolt adapted to reciprocate rearwardly and forwardly in the receiver and to rotate into locked position at the end of its forward stroke, said bolt having a lug to guide its movements, the forward portion of said receiver connecting with the barrel of the gun and the rearward portion comprising a tube secured to the forward portion, said portions having intercommunicating slots to guide said lug, and a second tube rotatable within said first tube for closing said slots when the bolt is in locked'position, said second tube having a slot for said lug adapted to register with the slot of said first tube when the bolt'is unlocked. v

15. A gun comprising a receiver, a bolt arranged to reciprocate forwardly and rearwardly in the receiver and to rotate into locked position at the forward end of its stroke, the bolt having a lug to guide its movement, the receiver comprising forward and rearward portions connected end to end,

said portions having intercommunicating slots to guide said'lug, the slot in said rearward portion extending longitudinally of the gun to guide the reciprocationof the bolt and the slot in the forward portion bending circumferentially to rotate the bolt into and out of locked position, the forward portion having a thick wall to withstand the stresses incident to the rotation of the bolt and the rearward portion having a lesser thickness adapted merely to guide the bolt in its reciprocatory movement.

16. A gun comprising a receiver having tubular forward and rearward portions disposed endto end, a tubular locking member fitted into said forward portion, said rearward portion being fitted into said forward portion in abutting relationship to said member, and. a tubular shutter-rotatable in said rearward portion in abutting relationship to said member.

17. A gun comprising a receiver having tubular forward and rearward portions disposed end to end, a tubular locking member fitted into said forward portion, said rearward portion being fitted into said forward portion in abutting relationship to said member, and a bolt movable in said receiver into find out of lockingrelationship to said mem- 18. A gun comprising a receiver having tubular forward and rearward portions detachably fitted together end to end, a tubular locking memberfitted into said forward. portion, and a bolt movable in said receiver into and out of locking relationship with respect to said member, said receiver and bolt having interlocking abutments adapted to lock the bolt in closed position, and certain of said abutments having lubricant ducts leading to the abutting surfaces thereof.

19. A gun comprising a receiver, a bolt reciprocatableforwardly and rearwardly in the receiver and rotatableinto locked position at the forward end of its stroke, and sets of interengaging locking abutments on the receiver and bolt respectively to lock the bolt in closed position, one of said sets of abutments being provided with lubricant ducts leading to the abutting faces thereof.

20. A gun comprising a receiver, a breech closure movably disposed in the receiver to reciprocate rearwardly and forwardly and to rotate at the forward end of its stroke into locked pos tion, the receiver and closure having locking abut-ments arranged to interengage when the closure rotates into locked position and having an interfitting lug and interrelated with said abutments so that said bend extends circumferentially through an angle at least of the order of one-half the circumferential extent of said locking abutments.

21. A gun comprising a receiver, a breach closure movably disposed in the receiver to reciprocate rearwardly and forwardly and to rotate at the forward end of its. stroke into locked position, the receiver and closure having locking abutments arranged tointerengage when the closure rotates into locked position and having an interfitting lug and guideway to guide theclosure, the locking abutments being inclined to the line of breech pressure at such angles as to hold the bolt closed at high breech pressure and to slide relatively to each other when the pressure drops to a low value automatically to unlock the closure, the guideway having a longi- "tudinal portion and an oblique portion joined 15 said lug and guideway being interrelated 20 with said locking abutments so that said bend and oblique portion extend circumferentiall'y through angles whose ratio is approximately four-sevenths.

Signed by me at Cleveland, Ohio, this 25 18th day of December, 1919.

oscAn v. PAYNE.