US2468784A

US2468784A - Autoloading pistol

Info

Publication number: US2468784A
Application number: US552456A
Authority: US
Inventors: Hal E Seagraves
Original assignee: Individual
Current assignee: Individual
Priority date: 1944-09-02
Filing date: 1944-09-02
Publication date: 1949-05-03
Anticipated expiration: 1966-05-03

Description

May 3, 1949. H. E. sEAGRAx/Es AUTOLOADING 'PISTOL Mom, mm, .E bm. l

May 3, 1949. H. E. sEAGRAvEs AUTLOADING PISTOL 4 Sheets-Sheet 2 Filed Sept. 2, 1944 IN V EN TOR.

May 3, 1949.

H. E. SEAGRAVES AUTOLOADING PI S TOL 4 shets-sheet 5 Filed Sept. 2, 1944 \NVENTOR @M5 E s y m @25:2 :2:: t i ai H Wl, m. E .IQ @S E .IQ KQ ..l QQ QQ i: f

IMaly 3, 1949.

H. E. SEAGRAVES AUTOLOADING PISTOL 4 Sheets-Sheet 4 Filed Sept 2,1944

INVENTOR v Hagnm mwN E mNN mo mw a w. ou SN mom mNT, iowmw marl; E;

for admitting barrel gas to the space.

Patented May 3, 1949 UNITED STATES PATENT @FFICE 4 Claims.

This invention relates to pistols and has for its object the provision of an improved autoloading gas-operated pistol. The improved pistol of the invention comprises a receiver having a breech bolt therein, a barrel connected to the receiver which is oblong in cross-section with a space in the upper part of the barrel for a gas piston operatively connected to the breech bolt, and a grip member for the barrel and receiver with a space in the grip thereof for a cartridge magazine. The pistol of the invention is characterized by the fact that its mass such as the receiver, breech bolt and barrel are xed at the instant of firing and accordingly do not move independently of other parts of the pistol.

The autoloading pistols proposed and constructed heretofore, both gas-operated and otherwise, have had such a preponderance of weight below the bore plane (a horizontal plane through the center of the bore when the pistol is in its horizontal firing position) that ring causes a violent upward flip of the muzzle. This, of course, is accentuated by the position of the gri-p which results in an upward force component. The upward flip of the muzzle contributes to inaccurate shooting and results in sighting complications when changing from one distance to another. The preponderance of weight below the bore plane has been due to the arrangement of the essential elements below the bore plane and the proportioning of the various parts. The pistol is peculiar among guns for the reason that it must have maximum low weight limits, regardless of the caliber, it is semi-automatic, firing once each time the trigger is pressed, it must have a grip below the bore to permit sighting, and it must be held in the outstretched hand. The hand is very yieldable under the terric impact of the explosion, and actually has little influence on the upward flip of the muzzle at the instant of firing, while the bullet is in the barrel.

In one of its main aspects, the ivention provides an autoloading pistol with such :a proportioning and arrangement of the supporting structure and operating mechanism, both below and above the bore plane, that the center of mass is at or above the bore plane and the upward ip of the muzzle is substantially reduced. The invention provides an improved barrel which is narrow and deep in cross-section (oblong) with gas-operated means in a space above the bore for operating the breech bolt, Which has a preponderance of weight 'above the bore plane, together with means The barrel and receiver are preferably unitary and may advantagously be integral as when formed of a single piece of metal. The barrel-receiver is detachably connected to a grip member comprising space and mounting means for the trigger, sear, hammer and magazine. The grip member is constructed as light as possible and may be made of steel in which case it is skeletonized to reduce weight in the lower part of the pistol. The grip member may also be formed of a molded plastic material, or oi magnesium alloy, `aluminum or aluminum alloy castings. These light weight molded and cast materials not only simplify construction but greatly reduce the weight in the lower part of the pistol.

One of the features of the invention is the provision of a pistol with a fixed barrel and receiver with no exterior moving parts in the automatic section. In one embodiment of the invention means are `arranged at the rear end of the receiver for the manual operation of the breech bolt, and the sides and top of the receiver are free of exterior moving parts, the only opening in the receiver being for ejecting the empty cartridge cases. This is an important feature in view of the fact that the receiver and barrel are iixed with respect to each other and the grip member.

The invention, in another of its aspects, provides a very simple and positive sear release comprising a trigger rod which is disengaged from the sear by the backward movement of the hammer and reengaged with the sear after the hammer is cocked.

Another feature of the invention is an improved means which automatically locks the hammer each time it is cocked by means of a safety sear and which is operated by a linger release on the forward face of the grip. This construction provides a safety feature without introducing any moving element in the heel of the grip. Devices mounted in the heel of the grip which are pressed in by the palm of the hand to release the hammer are very annoying to target shooters who prefer a iixed heel against the hand.

Still another feature of the invention is the provision of a very simple mechanism for holding the breech bolt in its open position when the magazine is empty and which automatically closes the breech bolt when a magazine with at least one cartridge is inserted into the grip. lA pivoted spring-pressed member on one side of the receiver engages the breech bolt each time the breech bolt moves rearward with the magazine empty or removed. Means on a side of the magazine actuated by the cartridges prevents the spring-pressed member from engaging the breech bolt when a cartridge is in the magazine. rlhis permits target shooters, firing slow lire, to have the breech automatically opened and left open after each shot.

These and other novel features of the invention will be better understood after considering the following discussion taken in conjunction with the accompanying drawings in which Fig. 1 is a side View, partly in section, of a pistol embodying the invention;

Figs. 2, 3, 4 and 5 are Views along lines 2-2, 3-3, 4-4 and 5-5 respectively of Fig. 1;

Fig. 6 is a View of the bolt of Fig. 1 from above;

Fig. 6A is a fragmentary View from below of the slide;

Fig. 7 is a side View of the pistol of Fig. 1 with internal parts exposed;

Fig. 10 is a fragmentary exterior view of the rear end of the pistol of Fig. '7;

y Figs. 8, 9, 11 and 12 are views along lines 8 8, F43', II-II and I2-l2 respectively of Figs. '7 and Fig. 131s a side View of another embodiment of the' invention;

Figs. 14, 15, and 16 are views along lines I4-I4, |'5-`I5 and IIE-I6 respectively of Fig. i3;

Fig. 17 is a fragmentary view of the rear end of the pistol of Fig. 13 with interior parts exposed;

Figs, 18 and 19 are views along lines Iii-I8 and I`9-I9 respectively of Fig. 17;

I3Fig. 20 is a View from above of the bolt of Fig.

Fig. 21 is a side View, partly in section, of the barrel-'receiver portion of the pistol of Fig. 13;

n Fig. 22 is a fragmentary side View, partly in section, of still another pistol embodying the inventio'n;

Figs. 23 and 211 are views along lines 23-243 and 24-24 respectively of Fig. 22;

Fig. 25 is a fragmentary side view oi Fig. 22 and 2G is a view alongr line Ztl-26 of Fig. 24 with the' bolt moved rearward.

The' pistols illustrated in the drawings comprise three mainnparts, a barrel B, a receiver R and a member G. The barrel and receiver merge intoAeach other at the rear end of the cartridge chamberrand may be connected 'together in any suitable' way as a unitary structure. As shown in the drawings -they are integral having been formed by simple mechanical operations from a single bar of steel or equivalent metal. The integral barrel-receiver is removably attached to the grip member and the barrel is of oblong cross- Sectional shape having substantially iiat or Slightly curved sides with a preponderance of its Weight above the bore place.

The `pistol of Figs. 1 to 12 has a barrel-receiver with a longitudinal space extending from end to endythe space I in the receiver being substantially rectangular and the space in the barrel being a cylinder 2. The slide 3 is reciprocably mounted inthe space with the piston 4 in the cylinder 2 andthe cam part 5 in space I is rectangular at the top and partly cylindrical at the bottom. The forward end of the cylinder is closed with a screw plug 6 and the gas port I connects the cylinder 2 with the bore. The port I is close to the end of the bore and is easily accessible for cleaning. 'A'slot 8 in the top of the barrel receives the sight 9,- Whi'ch is slidable up and down against the plug U: The sight is secured in an adjustable position by the locking plug ID which bears against the sight. Advantageously, the slot II for a screwdriver in plug 6 receives the depending part of the sight and is accordingly prevented from turning. The plugs 6 and I0 not only securely close the end of cylinder 2 but provide means for elevating or lowering the iront sight and securing it in the desired position. The slide 3 has an eccentrically disposed 4cylindrical hole I2 for housing the action spring I3 which bears against the piston at one end and' the plate I4 on the pilot rod I5 on the opposite end. Piate I6 bears against the projecting lug I5 on the frame 4l of G. The cylindrical chamber 23' formed in line with the bore receives the cylindrical breech bolt 2| which has therein the firing pin 22 and ring pin spring 23. The lbreechhbolt has an upwardly extending turning lug 24 which engages with the rectangular slot I8 and helical cam slot 25 in the cam part 5 oi the slide (Fig. 6). The bolt has a springpressed-'pinetype ejector 28, extractor 29, and a. cam slot 35i for engaging the lug 3| on the 4iiring pin, two locking

lugs

32 and 33 on one side, and a locking lug 34 on the opposite side. AThe lugs 32 and 33 travel in the guide groove 33 during reciprocationoi the bolt and enter locking slots 3i and 38 when the bolt is turned to its locked position. Lug 3A travels in guide slot 39 and enters the ejection opening 40, bearing against the rear edge thereof when the bolt is turned to its locked position. The side grip plates l2 and are attached to the slide for manual operation of the bolt and these reciprocate with the slide, in the guide slots 44 and 45. n

The under portion oi the barrel has a depending wedge-shaped block 46. The barrel-receiver and assembled elements' just described areremovably attached to the grip member G in a very simple manner. The projecting lug li on the heel of the grip member frame 4'! fits snugly into the space I and the block 4@ lits snugly in a wedge-shaped slot in the front end of frame 41 (Fig. 8). To remove the barrel-receiver from the grip member, the cotter pin 48 is pushed out and the barrel-receiver may be pulled forward. The lug I6 secures the barrel-receiver at the rear and block 46 secures it at the forward end.

The grip member frame 4'! may be formed of steel, in which case it is cut away as much as possible to reduce its Weight, or it may be formed oi alloys of aluminum or magnesium or a plastic material as will be more fully described hereinafter. The frame illustrated has cut out open sides which are covered with the wood grips 49 and 5G secured in position by screws 5I and '52. The central part has a chamber 53 for receiving the box magazine 54 which is held in position by the catch 55. The hammer is pivoted on the screw 5'? and is driven by the tension coil spring 58 secured to the frame by screw Sii and to the hammer by pin El. The hammer has a cam shoulder 62 projecting to the right and a depending lug E3. The' trigger-operated sear 64 is pivote'd on the screw-t5, has an upward extension G6 for engaging the notch 5'! on the trigger rod 6B and a shoulder 39 for engaging the hammer notch it. The scar compression'spring II is secured in a recess I2 in the frame and ts over a nipple 'I3 o-n the sear which holds it in position thereon'.

As best shown in Figs'. 3 and 11, a safety sear 'I4 is alsol pivoted on pin 65 and it has a shoulder 'I5 for engaging the hammer in the same manner als sear 6'4. The coil compression spring 15'io'i`- sear I4 is securi'eclv in the recess 'Hin the frame and fits over the nipple i8 on the safety sear which secures it in position thereon. The safety sear always catches the hammer in the same manner as sear Sil. The safety sear is operated by a release button S so arranged as to be pressed inward by the large or second finger, and the hammer cannot be released until button 80 is pushed in. Button 80 is connected to a U-shaped bar 8| which slides in a slot 32 inside the grip |39 (Fig. 9) and engages a slot 33 in the lower end of the safety sear. The flat spring 3d is attached to the frame by screws 85 and Si@ and the upper forked end 8l thereof ts into a slot 08 in the button 80 normally forcing the button to the projecting position shown in the drawings with the bar 3| out of bearing contact with the slot 83 in the safety sear. By pressing the button 33 inward, the safety sear is moved out of contact with notch 10 and the hammer may be released by pulling the trigger. The lower part 30 of the spring 8f3 bears against the magazine catch 55 and holds it in its locking position (Fig. l). It will thus be seen that spring 83 performs a dual function. Catch 55 can only be released by pushing it forward, an advantage when the gun is used in the brush.

As shown in Figs. 1 and 4, thel trigger 9| is pivoted on screw 32 and has a bifurcated upward lever arm 913 with the trigger rod 33 therein and pivoted thereto by the pin 05. The trigger rod is urged to the rear by the coil spring which may be adjusted for tension by the screw 91. The spring 96 not only sets the trigger rod in position for actuating the sear, but it regulates the trigger pull and this may be varied by screw Si?. The coil spring 93 around the screw 32 has one arm 33 bearing against the frame and another arm 33 hooked over the top of the trigger rod. As thus arranged the spring turns the trigger rod counterclockwise so that the notch el therein will snap down over the sear top 66 when in proper position. It will be seen in Figs. 1, 2 and 3 that the trigger rod has a U-shaped portion permitting it to operate around the magazine and inside the grip 50.

Referring to Fig. 1, it will be seen that the f hammer is pushed backward by the bolt beyond the cocked position of Fig. 7 and that the cam shoulder e2 has lifted the trigger rod 08 upward disengaging the notch 61 from the top 33 of the sear. The sear 6d is accordingly free to engage the hammer whether the trigger be held or released. When the bolt travels forward the hammer follows it until it is caught by both sears as shown in Fig. 7. (Safety Isear Hi has no connection with the trigger.) hammer drops the cam shoulder 32 permitting the trigger rod to rest on the top (i6 of the sear, if the trigger be held, and the notch Sl to drop over the top 60 if the trigger be released. In any event, when the trigger is released and the hammer is cocked, the notch (il will always engage the top 65 of sear 04.

The safety bar |02 pivoted on screw 00 has a hub |03 which cooperates with bushing H03 to center the Ispring 58 on the screw (Fig. 12). The safety bar has a channel |35 and a flat end H06 (Fig. 1). In the safe position shown in Fig. 7, the channel |35 straddles the lug 63 of the hammer preventing it from moving regardless of the position of the sears and the end |06 engages both sears blocking them from movement and the hammer is triple locked. In the non-'safe position of Fig. 1, the safety bar is pushed down out of engagement with the hammer and the sears. The notch |07 in the sears permits them to be This movement of the turned and to clear the at end |06 when the safety bar is in the position of Fig. 1. The safety bar is operated by an exterior thumb button |08 which is connected thereto by screw |03 through a slot 0 in the side of the frame 41. As best shown in Fig. 1l, the safety button has two flattened ears which bear against the side of the frame by spring action. The frame has four shallow grooves lll, ||2, ||3 and I|4 in which the heads H5 and l i6 on the inner end surfaces of the ears make engagement. In the safe position of Fig. 11, beads ||5 and ||6 are in grooves l l and i3. In the non-safe position, the beads l i5 and i i3 will engage beads l I2 and l I4 respectively. The button |08 cannot be set in the Isafe position unless the hammer is cocked.

As shown in Fig. 1, the bolt is ready to start forward under the driving action of spring I3. The bolt is pulled forward by the lug 24 and is prevented from turning during its longitudinal travel by the

lugs

32 and 33 traveling in guide 36 and lug 33 traveling in guide 39. Fig. 6 shows the bolt as it reaches the end of its forward stroke with the cartridge pushed into the barrel chamber. The bolt is in its unlocked position and is free to slide rearward. Further forward movement of the slide 3 will result in the cam 25 turning the bolt counterclockwise to its locked position with the

lugs

32 and 33 in the locking slots 3l and 33 (Fig. 1) and the lug 36 in the ejection opening 10. After closing the bolt, the slide continues to travel forward a short distance, say around three-eighths of an inch, the lug 24 entering the rectangular slot I8 which locks the bolt in position preventing it from turning. The bolt is now locked with three

lugs

32, 33 and 34 and cannot turn.

The lug 3i on the firing pin also travels in groove 3G and is thereby prevented from turning with the bolt. As shown in Figs. 1 and 6, the firing pin is held to a rearward position beyond the reach of a cartridge by the lug 3| bearing against the end of the bolt. When the bolt is turned counterclockwise to the locked position the lug 3| assumes a position in front of cam 30 and the ring pin may be driven forward by the hammer into contact with the cartridge except when the bolt is locked.

When a cartridge is red and the bullet passes beyond gas port l, the gas rushes into the cylinder 2 and drives the slide 3 rearward. (Fig. 22 shows a piston in the firing position.) The slide travels rearward about three-eighths of an inch, the length of rectangular slot i8, without acting upon the bolt lug 24. rIhe forward inclined face in cam 25 strikes the lug 2li and turns the bolt clockwise to its unlocked position Shown in Fig. 6. The momentum of the slide in cooperation with the residual gas pressure, carries the bolt to the rear as shown in Fig. l ejecting the empty cartridge case. A fresh cartridge rises to the position shown in Fig. 1 and is ready to be pushed into the chamber of the barrel on the return of the bolt.

The pistol shown in Figs. 1 to 12 has a bore of about .35 caliber and the barrel is ve and fiveeighths inches in length. This pistol may be provided with a bolt catch similar to that of Fig. 22 or with a hammer spring similar to that of Fig. 17 if desired.

The spring of Fig. 1 is especially important in pistols constructed for long cartridges because it permits the full use of the grip for the magazine and does not make the grip unduly wide and cumbersome. Moreover, the spring is close to the bore eliminates weight inthe `lower part of 'grip `iaie'emk'ie'.

*rnefpistei illustrated in Figs. 13 to 21 comprises -blrrel-receiver B-#Rf`slidably attached to the rip member Cf-in a manner similar to' that 0f Figc-1.v The .grip member is formed by casting or molding-and the supporting frame |20 is a unitary structure with all of the large cavities and eiftferior 'shapelforni'e'd therein by the casting. or molding operation; It may be cast of aluminum orfiiignesium alloy or formed of a molded plastic materialsuch` as Toollte.

`Gas: from the bore is admitted to cylinder |2| throughvori'fice |30 which is bored in a removable plug 3| fitted snugly in a transverse hole through the barrel between the bore and the cylinder l2 l. The plug is' providedwith an ear |32 which fits atslot' inl the barrel insuring proper positioning of ythe plug.A The plug is held in position by the screw |33 and may easily be removed for cleaning. The slide |22 has a depending lug |34 which engages the helical cam 'slot |35 in the breech bolt |35. The boltis reciprocably mounted in a cylindrical space |31 in the receiver andin line 'with the bore. As best shown in Fig. 19, the metal between cylinders |2| and |31 is cut out to form the guideway |38 in which lug |34 travels and.l the slide is prevented from turning. The projection |40 on the firing pin |4| and the locking lugs V|42 and v|43 travel in the guideway during'reciprocation of the bolt. The ring pin has 'aspiring |44 for holding it rearward. As shown in Figs. 19 and 20, the bolt is in its locked positionfwitli lugs in locking recesses |45 and'll and the 1ug |34`is"in the rectangular part |41 of .the complots-|35 `and the bolt is prevented from turning. The turning of the bolt has setthe recessed part of'cam |49 infront of projection |40 on the firing pin' and the' firing pin is free .tobe driven .forward by the hammer.

VAs shown in Fig. 21, the slide `has moved rearward andthe lug |34 has turnedthe bolt clockwise toits unlocked position. The slide'and bolt arefnow ready to travel rearward under the pressure fof the gas fromI the bore. The turn of the boltdur'ing the unlocking causes the projection .|40 to'move the ring pin rearward by the engagement with the cam slot` |49 andthe firing pin cannot contact cartridge. The'rearward travel of the slide `and bolt compresses the action spring |24 which returns the same to their forwardv positions.I and locks the bolt. This locking is done by lug |34 striking the forward helical face of cam slot |35resulting in thebolt being turned counterclockwise to the position shown in Fig. 20. rlhe .bolt `has an ejector (not shown) similar to that of Fig. 1 andan extractor le!) which enters afvclearance recess inside cylinder |31 on the rearward travel of the bolt.

The bolt is operated manually bythe ribbed plates |55 and |56 which travel the length of slide travel |22 in `recesses |51 and |58 on opposite sides of theffknarrel,A l Plate V|55 hasan integral projectlngbar 460 which is inserted through a long narrow slot |6| onr the left side of the barrel,` through a short rectangular slot |62 in the slide, and through another long narrow slot |63 on the right side of the barrel. The plate |56' butts against the end of bar |60 and is secured thereto by sc-rews |64 and |65. To operate the breech bolt manually, the plates are gripped between the thumb and fore-finger and are pulled rearward until the slide and bolt reach the end of their stroke. 1f the plates are released the action spring drives the slide and bolt forward to the locked firing position.

The pistol of Fig. 13 has a sear and trigger mechanism similar to that of Fig. l but the hammer is driven by a compression spring |51 in the gripwhich connects to the hammer |68 by Vrod |09. I may use with the pistol of Fig. 13 a. safety seaiand hammer spring similar to 'those of Fig. l and a bolt catch similar to that of Fig. 22.

As shown in Figs. 17, 18 and 19', the safety mechanism comprises a push button formed of two parts |1| and |12 which are connected to gether by screw |13. Both parts have square ends which iit into square holes on the Opposite sides of the frame |20 and are, accordingly, prevented from turning. Part |1| has a slot |141connecting with two hemisphcrical recesses |15 and |16 in which the plug |11 is pressed by the coil spring |18 held in position in the frame by'screw |80. Part |12 has an upward extending bar |8| which, when in the same position shown in Figs. 18 and 19,A blocks the hammer preventing it from moving'towards the firing pin, and anangularly disposed depending bar |82 which blocks the sear preventing it from releasing the hammer. If button |1| be pushed inward, the plug |11 backs out-of recess |16, travels through slot |14 and snaps into recess |15 securing button |1| in the non-safe posi-tion flush with the side of the frame l2 Simultaneously button |12 projects to the right and bars |8| and |82 `enter the spaces |83 and 34 to the right side or the hammer and scar releasing them' and permitting the trigger rod |85 to operate the sear |85 and release the hammer. The safety mechanism of Figs. 13 to 21has several positive operating advantages in a pistol. For example, in the safe position, button |1| is in the way of the shooters thumb and no time will be wasted in trying to re when the safety is set in the non-firing position. When in the nonsafe or firing position, button |12 projects to the right where it is easily seen even when the pistol is in a holster. Moreover, the safety member cannot be set in the safe position unless the `hammer be cocked.

The barrel illustrated is six and three-eighths inches in length and is bored for about 35 caliber.

When the pin |81 is removed, the barrel-receiver may be slid free of the grip member G. The slide, action spring, pilot rod and breech bolt slide out of the barrel-receiver towards the open rear. The pistol of Figs. 13 to 21 is of Very simple construction being formed by the simplest machining operations.

Figs. 22 to 26 illustrate only theupper part of the grip member G, it being understood that the lower part thereof may be similar to-that shown in Fig. l or 13. The barrel-receiverhas a cylindrical space above the bore and extending from end to end in which is mounted the cylindrical slide |9|. The barrel is deep and narrow in cross-section having an oblong configuration similar to the barrels of Figs. 1 and 13. The fore ward end of the space is closed bya screwplug |92 yand connects to the bore by a gas duct |93.

The upward extension 94 on the frame 195 oi the grip member has a cylindrical projection 96 which lits into the cylindrical chamber lill in the receiver and in line with the bore, and the rear end of the barrel-receiver is thereby slidably coupled to the grip member. The front part of the grip member is slidably connected to the bar-- rel by the wedgeshaped lug 5% which slides into a wedge-shaped slot similar to that oi Fig. 8 and the two members are secured together by the pin 200.

The slide i9! has a central cylindrical space 20! a part of which is filled with lead 2li-2 to increase its mass and has a screw plug 293 with a cylindrical hole in which the combined action rod and pilot rod 20e is slidable. The rod slides through a hole 205 in the extension E06 and is threaded into the manual operating member The other end of the rod has a head Ztl slidable inside the space ZEM. The action spring Zlll bears against the extension |94 at one end and the plug 203 at the other end. Member 2% guide rails 209 and 2li! securely attached thereto as by threads. These rails pass through holes in the extension Edil and member 266 is thereby held in its upright position and is prevented from turning.

The slide has a depending lug 2l l which oper ates in a helical cam slot 2HE in breech bolt 253 similar to that of Fig. 20. The metal between cylinders Mill and lill is cut out to form the guideway 2M in which the lug 2li travels, pr.,w venting the piston slide 20| from turning. The locking lug M5 also travels in this guideway when the bolt reciprocates. In this form of the invention the bolt has two locking lugs and grooves therefore which are similar to those shown in Fie.. 20 and the extractor 23S may be of any suitable type.

One of the features of the pistol of Figs. 22 to The side of the magazine 22e has a slit 22'! near the corner and another slit 228 spaced inwardly therefrom, leaving a section 229 as a fairly easily movable flap. As shown in Figs. 24 and 26 the projection. 235i presses the flap 229 inward under the strong turning action of spring 22d. When the catch is in the position shown in Figs. 24 and 26, the lug 23! is swung in front of the bolt 253 and the bolt is locked in its open position. The bolt may be released by pressing the opposite outwardly projecting end 232 inward.

Normally. whether the magazine be loaded or empty, the flap lies iiush with the side of the magazine and when itis loaded the cartridges prevent it being pushed inward by the catch lug When the last cartridge has been removed from the magazine and when the bolt has moved to its rearward position, the spring 22d pushes the catch inward as described until the catch lug 23! takes position in front of the bolt and blocks it from closing. rThis action of the catch is possible because the flap yields permitting the catch 222 to be pivoted. The catch not only holds the bolt open when the last shot has been red but it holds the holt open even when the magazine is not used. The pistol may be used for single shot ring and the bolt automatically remains open after each shot with or without the magazine.

When a cartridge is red and the bullet goes past port its, gas passes therethrough into cylinder i9@ and drives the slide l 0l rearward against action spring 263, the lug 2i l operating in the cam groove i?! 2 to operate the bolt in the manner described in connection with Figs. i3 to 21. The manual operating member 2525 and rod 204 remain stationary due to their inertia and frictional resistance and the slide moves over the rod. When it is desired to operate the breech bolt 213 manually, the member is pulled backward and the head 'Ztl engages the plug 2&3 and draws the slide and bolt rearward. When the motion has been completed the member 230 may be released and the action spring Zilli drives the slide and breech bolt forward to the locked position.

As stated hereinbefore, an important feature of the invention is the proportioning and arranging of the operating elements of the pistol to have more of the mass of the pistol above the bore plane than below. 1t is necessary to eliminate all unnecessary weight below the bore plane. This may be accomplished by cutting out all unnecessary weight in the grip member, especially when the grip member frame is made of a heavy metal like steel. Since the grip member of the invention is under very little strain no heavy sections are necessary.

In determining the weight of the pistol above and below the bore plane the magazine is removed and the barrel chamber is emptied. The hammer is set in position against the ring pin, the position it occupies at the time of ring. The pistol may have such excess weight above that it overcomes the weight of the magazine. I have found that the rst shot from a fully loaded automatic does not strike the same place as the last shot, when the magazine is empty and that the moet consistent accurate shooting slow re will be accomplished when the magazine is removed. The pistol, nevertheless, operates automatically especially in unloading, and the term autoloading as used herein covers both loading and unloading.

The formation of the grip member frame of a light cast or molded material gives distinct advantages in the way of low weight and low cost. lt may be cast of aluminum or the low-silicon aluminum alloys similar to the engine piston alloys, or of magnesium alloys containing say, from 0.05 to 3 percent manganese, or the magnesium base alloys containing from 0.1 to 12 percent of aluminum and from 0.05 to 1 percent of manganese. When the grip member frame is cast from a light metal the mechanical operations are reduced to a minimum and are comparatively simple. The trigger and parts of the magazine and magazine catch as well as certain screws and parts of the safety may be made of such metals.

The grip member frame may be molded from resins such as vinyl, phenolic, or methacrylates. The thermosetting resin having the trade name Toolite has distinct advantages because of its light weight and high compressive strength of around 20,000 pounds per square inch. Moreover, it may be cast to very accurate dimensions.

In view of the simple mechanical operations required to form the barrel-receiver, it may be made of stainless or other corrosion resistant steel the use of a plastic or light metal grip member frame gives a pistol adaptable for use in damp climates.

The slide of Fig. 22 is weighted with lead and 'it is to 'befunderstood that the slides of theother embodiments of the invention may be weighted with lead, depending on'the caliber, length of barrel and diameter ofthe piston.

I claim:

1, An autoloading pistol comprising a receiver, a barrel connected to the receiver, said barrel being oblong in vertical direction in cross-section,

`a grip member for the barrel and receiver having a space in the grip for a cartridge magazine, a breech bolt in the receiver, means for locking and unlocking the breech bolt in breech closing position with respect to the barrel, said means including a longitudinal space in the receiver and in the barrel above the bore extending from the Vrear of the receiver through the barrel, apart of a barrel connected .to the receiver, said barrel being oblong in vertical direction in cross-section, a grip member for the barrel and receiver having a space in the grip for a cartridge magazine, a breech bolt in the receiver, means for locking and 4 unlocking the breech bolt in breech closing position with respectto the barrel, said means including a longitudinal space in the receiver and vin the barrel above the bore extending from the rear ofthe receiver through at least the major portion of the barrel, a .part of the space in the barrelbeing a cylinder, a piston mounted in the cylinder, meansV extending rearwardly from and :operatively connecting the piston to the breech Jbolt, a gas duct connecting the bore with the cylinder `forward of theA piston to admit gas from the bore to drive the .piston rearwardly to unlock and move the `breech bolt rearwardly and eject the empty case, and means for forcing the breech bolt `and piston forwardly to vlocked breech closing position, the parts comprising the pistol being so proportioned and arranged that the mass above the bore plane is at least equal to the mass -below the bore plane.

"3. -An autoloading pistol according to claim 1 in which the space in the barrel above the bore extends completely through the barrel and a removable plug in the space closing it at the muzzle end forward ofthe gas port.

4. An autoloading pistol comprising a receiver, a barrel connected to the receiver, said barrelbe ing oblong inL vertical direction in -cross.section, a grip member for thez barrel and receiverhaving a space `in the grip for` acartridge magazine, a 'breech bolt inthe receiver, means :for locking `and unlocking the breech bolt in breech closing po sit-ion with respect to the barrel, said means llncluding a `longitudinal space in the receiver and in the barrel above the bore extending from the rear of the receiver into the barrel, a part of the .space in the ybarrel being a cylinder., a. piston mountedrin the cylinder, means extending rear- :Wardly from and operatively yconnecting the piston to *the breech bolt, a gas duct connecting the bore with the cylinder forward of the piston Vto admit gas from the bore to drive the piston rearbreech clos-ing position, a rear sight mounted on the receiver, and a -f-ron-t sightA mounted onfthe barrel, said sights being yboth rigid and fixed with respect to the bore and immovable by actuating parts of the pistol.

HAL E. SEAGRAVES.

REFERENCES CITED The following references are of record in lthe 'file of `this patent:

Number Name Date 570,388 'Ehbets Oct. 27, 1896 580,923 l'Browning Apr; 20, 1897 1813,694 'Fidgeland Feb. 27, `1906 934,158 Gates Sept. 14, 1909 944,606 Frommer Dec. 28,` 1909 992,854 Cobb zMay 23, 1911 1,041,928 vWesson '.Oct. 22,I 1912 1,163,516 Du-iTek EDec; 7, 1915 1,166,554 Smith Jan; 4,*19'16 1,291,690 Smith Jan'. 14, 1919 1,344,991 Cunningham June 29, 1920 1,387,460 Beet-s Aug. 16, 1921 i 1,388,856 Fox Aug. 30, 1921 1,430,662 Lewis Oct., 3, 1922 1,511,509 Diehm Oct. 14, '1924 1,520,671 Rosier Dec. I23, 1924 1,711,874 Brinkerhoff May 7, 1929 1,759,277 Revelli May v20, 1930 `1,835,286 Dickinson Dec. 8, 1931 2,088,268 Lauf July 27, 1937 2,287,032 -Garand June 23, 1942