US2466929A - Electric firing means for automatic guns - Google Patents

Description

-pril 12, 1949.

J. P. CATLIN ETAL ELECTRIC FIRING MEANS FOR AUTOMATIC GUNS Filed Dec. 22, 1945 INVENTORS JOHN PC'ATL /N PAZ/L F DARBY @www AG ENT Patented Apr. 12, 1949 ELECTRIC FIRING MEANS FOR AUTOMATIC GUNS John P. Catlin and Paul F. Darby, Fairfield, Conn., assignors to Remington Arms Company, Inc., Bridgeport, Conn., a corporation of Delaware Application December 22, 1945, Serial No. 63.6,904

9 Claims.

The present invention relates, in general, to firearms, and, more particularly, to electric firing means for quick firing guns, typical of which is the automatic firearm shown, in part, in the Marc Birkigt patents, No. 2,159,126 and No. 2,159,127, May 23, 1939. It will be understood, however, that the particular gun shown is by way of illustration only and that the invention is not limited thereby, but includes all modifications and applications within the scope of the appended claims.

Of recent development is a cartridge having an electric primer for use in automatic quick firingv guns. It is proposed to re this cartridge by conducting a high voltage charge, such as the discharge of a condenser, to the electric primer. Early experimental work resulted in the development of an electric bolt which, in general, comprises a bolt provided with a contact pin instead of the customary firing pin, the contact pin being insulated from the bolt and charged by engagement with a conductor carried in the bolt. This conductor has a make and break connection with a condenser terminal which is fixedly supported in the side of the receiver and arranged so that as the bolt moves into battery, the contact pin will be charged and fire the cartridge. The gun is grounded to provide the return circuit.

These experimental electric bolts proved impractical due to a breakdown of the insulation long before the gun had served its normal life and to a tendency of the contact pin to strike the electric primer with substantially the same energy and rigidity as the firing pin in percussion guns with the result that electric primers frequently failed to fire.

An object of the present invention is the provision of improved electric firing means for firing cartridges having electric primers. A further object is to provide a breech bolt with improved electric ring means which will stand up throughout the normal life of the firearm and which will be dependable.

These and other objects, features and advantages of the invention will be more particularly described in the following specification, having reference to the drawing, in which:

Fig. 1 is a fragmentary side elevation, partly in section, of an automatic firearm embodying the electric bolt` of this invention.

Fig. 2 is a fragmentary plan view, partly in section, on line 2-2 of Fig. 1.

Fig. 3 is a vertical section on line 3-3 of Fig. 1.

Fig. 4 is a diagram of an induction firing circuit for use with the electric bolt shown in Figs. 1 and 2.

Fig. 5 is a diagram of a capacitative firing circuit adapted for use with the electric bolt shown in Fig. 1 and 2.

Fig. 6 is an enlarged section view of one-half 'of the electric firing means shown in Fig. 2.

Fig. 7 is a fragmentary side elevation of the front end of one of the slides showing the firing means retaining lug.

Fig. 8 is an isometric view of the forward portion of the right hand slide. The view is from a point to the rear of the front end and from the inside or to the left of the slide as properly oriented in an assembled gun.

The firearm chosen to illustrate the present invention is shown, in part, in Figs. 1, 2 and 3, and comprises a substantially rectangular receiver I0 provided with an upper cartridge feeding aperture II and a lower cartridge ejection aperture I2. A barrel I3 is secured in the forward end of the receiver. Mounted in the receiver for reciprocable sliding movement is the breech mechanism which comprises a breech bolty I4 having a longitudinal aperture I4 and a pair of slides I5 and I6, the latter being supported on opposite sides of the bolt and slidable longitudinally relative thereto. Supported within the bolt is an electric firing means indicated generally at I'l which is cooperatively associated with the pair of slides I5 and I6 so as to be displaced within the bolt by relative movement of the slides and bolt in the manner and for the purpose hereinafter described.

The bolt I4 is substantially identical to the bolt shown and described in the above-identified Birkigt patents, the recoil movement of which may be initiated by suitable gas operated means comprising a movable element I8 having a member I9 rigidly secured thereto arranged to engage and actuate the slides I5 and I6. The bolt is adapted to be urged forwardly into breech closing position, hereinafter termed its firing position, by an action spring 20 working against a suitable thrust collar in the bolt as hereinafter described. Slides I5 and I6 are arranged to move relative to the bolt for locking and unlocking the latter in and from firing position in the receiver. To this end the bolt is provided with a pivotally mounted pawl 2l oscillatable between upper and lower positions and arranged normally, that is to say, when in its upper position, to lock together the bolt I4 and slides I5 and I6 so as to prevent relative movement thereof, which is the relationship of the bolt, slides and pawl 2I 3 whenever the bolt is rearward of its firing position. When, however, the bolt is in ring position and the pawl 2| is moved into its lower position, it locks the bolt I4 in firing position and unlocks the slides l5 and I6 which are then free to move forwardly relative to the locked bolt.

This supplemental movement is affected by the;

provision of springs 22` and 22 mounted? inhous-I ings 23 and 23 respectively in each slide, each spring bearing at one end against a suitable lug# 24 projecting from the adjacentsideofthebolt.

The forward movement of the slides I5 and;

I6 relative to the bolt is adapted to move the electric firing means |1 into engagement witlr the electric primer p of a cartridger C" in: the breech of the barrel. On firing a cartridge, the force of the gases actuate thermemberflS; which: in turn moves the slides together with the. elec.- tric ring means l1 rearwardly with respect to the locked bolt, thereby elevating the pawl 2| and unlocking the -bolt from thereceiver andenabling` the rearward recoil of the bolt and slides;`

TheA present invention is concerned with the construction and means for operating the` improved electric ring means which, as shown, is slidably mounted inthe aperturei I4'4 ofVA the bolt. firing; means takes the place of aconventional percussion ring pin and comprises ahollow cylindrical body member 25 provided' at its forward end with an enlarged substantially conical'head 26,' the base of which comprises# ane annulusn 2`|J ofgreater'diameter than `the diameter of the -bodyf member so asl to form a substantially square` shoulder 21' therewith. The diameter off the shoulder 27" is, however, less thanthev inside diameter of theaperture |4 of the boltfsothat the periphery'of the annulus will be spaced fromthe; walls' of the bolt aperture,- seefFig. 2. The

rear end of tl'iebody member is exteriorly threaded'` and provided with a cap-28, the outside diameter of' the cap :also being.r less than the inside diameter of the bolt apertureu so thatv the periphery of; the cap will clear the adjacent walls of' the aperture.

A two-part'` electricalcontact element is resiliently mounted in thef longitudinal aperture 25" of the body member and comprises a contact pin; 291 and', a combination. spring pilot and anvil*` 30; The shank of` the contactpin is tapered" adjacent, its forward end and. terminates in a sharp conical' point 3|. The rear end oftheV pin; has an annular shoulder 32, the forward' edge: of. which is adapted to abut an annular shoulder 3.3." formed inA the aperture 25'i of the body25jto limit. the forward movement ofthe pin.4

A'reduced portion 344` of' the pin rearwardly of its` annular shoulder 32 provides support forthcforward end of a coil compression, spring 35, therear end of which` abuts` an annular shoulder 36 of the spring pilot and anvil 3,0. The forward end4 of the latter is normally spaced a short` distance from the rear end of the contact pin 2'9' and constitutes an anvil to limit' the rearward travel of the contact pin. To; this end the rear end' of the spring pi1ot'3ll seats againstl the cap 28 so that the force of the, compressed spring acts normally to resiliently holdthe, shoulder 32' of the Contact, pin 29 against the annular shoulder 33' of the aperture 25 with they conical point. 3| of the pin extending forwardly beyond the face of the bolt.` Thus, when. contact is made with the electric primer of a cartridge, the contact pin Z9 is able to yield and move rearwardly against the force of the compressed spring 35,

Referring to Figs. 2` and? 6, the electricu the anvil 30 acting to limit the rearward movement of the pin. In its rearward position, the conical point 3| of the pin is substantially flush with the face of the bolt. 'I'he tapered constructio`n of the contact pin and its sharp conical point 3| are provided in particular so that the aperture 3ST in the-face of the bolt may bei as small as possibleinorder to preclude blanking the electric primer during ring. In the present embodiment, the aperture 31 is formed in a diskslfiapedlmembcr` 33` which is inlaid in a counterbore 39" formed in the face of the bolt.

The body member 25 and its electric contact pinfZS- aresupported'- to travel freely within the aperture |24 of-the bolt by front and rear guide bushings 4U' and 42 respectively, each of which comprises alV cylindrical member having an annular enlargement 43 and 44 respectively at one end of an outside diameter such as to make a smooth running t within the aperture I4 of the bolt; and anuannularflange 45 and 46 respectively at ritsf opposite end, each flange being of l'ess diameter than the aperture I4 so asto cl'earv the' walls-thereof.

It will`A benotecl thatall corners of the bushings? areiround'ed'and that the front edge of the enlargementof theforward bushing 40 has a slight taper; The guide bushings are mounted at opposite-i ends of the cylindrical body member 2'51 and insulatedf therefrom by dielectric tubing or sleeves 4I. Suitable insulating washers 48, comprising' abone hard gray vulcanized ber, are also' provided forV insulating the faces 43| and1441lL of thel guide bushings from the adjacent surfaces ofl the cup` 28 and the shoulder 215Y of'the bodymember. A second pair of insulating wasllers` 491 are provided on the body memberbetween theopposed faces of the anges in'- diameter tothe flanges 45r and 46; but which is" not: insulated from the bodyrmember being arranged to makevl a` good' electrical contact therewith for the purpose hereinafter described.

The; assembly of bushings 43 and 44, insulating sleeves 41, insulating washers 4B and149and the contact' ring 5|l1is securelyheld on the body member 25 by coaction of the shoulder 21'* and thelscI-Aew'threadedcap 28.; the latter being adapted; tol be turned up on the threaded end of the bcdyrmember 25 to force the, entire assembly forwardly'against` theshoulder 21"; A pin 28' mayJ beprovided? to 'lock-f the threaded cap Zfin finali position. The contact pin 29, threaded cap` 28 and'body: member 25' are-thus insulated fromJ the walls of the bolt but are in electrical contact with the contact ring" 50T.

The electrical firing means' |'l" is arranged to be moved'back and' forthr in thebolt aperture by the slidesA |J5and I6'. To this end, each slide is provided! at'its forward end*y andladjacent the bottom edge of' its inside facel |5| and: I'l respectively with an integral horizontally disposed laterally projecting lug; 52and 53:` respectively (see Figs. 2 and" arranged to project4 through rectangular slots` |42 and |431 inl adjacent walls of the bolt. Each lug is substantially rectangular in cross section,` the edgesl of" the forwardand rear ends of; each' lug being semi-cylindrical surfaces' corresponding in curvature to the rounded ends of the slots |42 and |43- in the bolt; The length of each` slot |42 and |43 is,, however, greater than the length of a lugso as' to enable" each lug; to have longitudinalmovement within its respective slot. Formed integrally on the longitudinal edge 55 and 56 respectively of each lug are a pair of spaced parallel vertically arranged ribs 51, 51 and 58, 58, respectively, each rib being substantially rectangular in cross section, as shown in Fig. 2, and provided with a downwardly and inwardly sloping bevelled face 51' and 58 respectively. Between each pair of ribs 51, 51 of the lug 52 of the righthand side is an aperture 59 which extends through the lug to the outer face of the slide, the longitudinal axis of the aperture 59 being substantially at right angles to the longitudinal axis of the slide and in a horizontal plane parallel to the horizontal plane of the lug. Fixedly secured within the aperture 59 by a pin is a fiber insulating bushing 66.

Referring to Fig. 2, the slide l5 is provided with a relief groove 6|v which extends longitudinally along the outer face I5?. of the slide from the front edge thereof rearwardly to a point adjacent the forward wall of its spring retaining housing 23. The groove 6| is substantially rectangular in cross section and is blended at its rear end by a radius into the outer face |52 of the slide. The groove 6| lies in the horizontal plane of the lug 62 and intersects the Ibushed aperture 59 thereof as shown in Fig. '1.

The lug 53 of the slide I6 on the left-hand side of the bolt is not provided with an aperture, but the outer face of the slide has a groove 62 which extends longitudinally rearwardly from the front edge of the slide. The rear end of the groove is blended by a radius into the outer face |62 of the slide, the overall length of the groove being such as to provide the lead required for induction ring purposes as hereinafter described.

Freely mounted in the bushed aperture 59 of the right-hand lug 52 is an intermediate contact member or conductor 64 which is provided with a rounded head 65 at its inner end and a radius at its outer end. The head E5 is adapted to be held at all times opposite the contact ring 58 of the electric firing means |1 and to this end the lateral spacing of the vertical ribs 51, 51 and 58, 58 of the respective lugs 52 and 53 is such that on assembling the firing means |1 between the lugs of the right and left-hand slides, as shown in Fig.

2, each pair of ribs will make a close fit in the space between the shoulders 43 and 44' respectively of the forward and rearward bushings 46 and 42, thus precluding any longitudinal movement of the firing means relative to the slides and securely holding the contact ring 56 opposite the head 65 of the conductor 64. Thus, longitudinal movement of the slides relative to the bolt, which is permitted by the relationship between the length of the slots |42 and |43 in the bolt and the respective lugs therein, will in turn move the electric firing means |1 relative to the bolt so as to positively advance and retract the contact pin 29 to and from the face of the bolt.

On the wall of the receiver I0 adjacent the breech end thereof is shown a terminal supporting means for the primer ring circuit.

One type of ring circuit is the induction circuit indicated generally in Fig. 4 comprising a suitable source of electrical energy which in the present embodiment is a twenty-four volt battery B for supplying direct current to a primary coil 88, When the circuit through the primary coil is closed, current will build up in the primary coil, during which a relatively high voltage will be induced in the secondary coil 85, the magnitude of the induced voltage being determined by the same factors which determine the ratio of voltage in the primary and secondary coils of a conventional A. C. transformer. With this circuit, two terminal supporting means are used each comprising ya substantially rectangular block 61 consisting of aluminum or other suitable material secured to the receiver wall by fastening means 68. Each block is provided with a central counterbored aperture 69 and is supported on the receiver with its counterbored aperture opposite an aperture 10 in the adjacent wall of the receiver, a suitable ange 1| being formed integrally on the inside face of each block to iit into the corresponding aperture 10 in the wall of the receiver for properly positioning and securing the block thereto. Within each counterbored aperture 69 is a resiliently mounted terminal comprising a cylindrical member 12 having front `and rear guide bearings 13 and 14 respectively arranged to slidably engage insulating bushings 15 and 16 which are fitted into the counterbored .aperture 69. Projecting from the guide bearing 13 into therelief groove 6| of the adjacent slide I5 is a contact blade 11 having `an inclined surface adapted to be engaged by the radius of the conductor 64, as the slides move forwardly in the receiver, to urge the conductor inwardly and engage its head 65 with the contact ring 50 of the electric firing means. The blade 11 is projected into the path of the conductor 64 by the force of a coil spring 19 which is carried on a stem 12' of the terminal, the spring abutting 4at one end against the guide bearing 14 of the terminal and -at its other end against a centrally apertured metal terminal disk 88. The latter is mounted in a counterbored reY cess 8| formed in the adjacent face of a dielectric cover plate 83 secured to the terminal block. The recess 8| provides clearance for the outer end of the terminal stem 12'. A lead wire 84 for the terminal blade 11 in the right-hand side of the receiver is connected to the secondary coil 85 of a transformer, indicated generally at T in Fig. 4, passes through lan aperture 86 in the dielectric cover plate 83 and is secured in eng-agement with the disk by a solder joint. A lead wire 81 is similarly secured to the terminal blade 11 on the left-hand side of the receiver and is connected to the primary coil 88 of the transformerT. As may be noted by the inspection of Fig. 2, the pro,- trusion of the blade 11 of this terminal is limited by its enlarged ange to an amount less than that permitting it to ride in the bottom of the relief groove 62 of the slide I6. Thus, the lead wire 81 will not be grounded to the slide until, during the final forward movement of the slide, the blade 11 rides up the end of the relief groove and along the face of the slide.

It will be understood that the voltage induced in the secondary coil will be created either by making or breaking the primary circuit. In the present embodiment, the induced voltage in the secondary coil is effected during the building up of current in the primary coil and is accomplished, after closing the ring switch S, by grounding the primary coil 88. This occurs when the termina-l blade 11 on the left-hand side of the receiver rides out of the relief groove 62 and engages th-e adjacent side of the slide |6 as the slides approach their foremost position .in the receiver. The lead or length of the relief groove =62 is determined by such factors as the time constant of the primary coil and the time required for the mechanical operation of the gun mechanis-m. In the present embodiment substantially two milliseconds elapse between the time the bolt is locked in breech closing position and the slides have, carriedV the` contactpinl k29y riorwarelly into y f Contact with an; electric primeras. f f c y kTheft/imc constant-,tof the primary coill llav musay f y therefore, be greater thanqtwomilliseconds and. the leadfof the relief groove will determine what c f ractionof thetwotmilliseconds time interval-willy be; allowed for currentvbuild; upy in ther primary c l c coilfthis fraction` being; such las toy insure high f y enough voltagein l,the secondary,y coilY 85.-y tol re f :theyk electrick primed kImrnediately prior 'tof the engagementk of thacontact pin Zawith anelecfk y tricr primer,y the# secondary 'terminal 'lf'l-y on ,ther

I kright-hand.side` ofthe receiver ycontacts kthe con+r c f yductor 64 on, theslide 115- and discharges the in` f y rduced chargeof.thesecondaryfcoil 85 to thel conf1 y c tactl pinr 29` andprirrleny pwhichr fires `the -cartriclge.I f

'.descrimed,above.y Moreover', the` cont'actpin ina f variably makes positive contact with the electricy f primer 'but' will rnot'strilze the primer hard` enough` l to rdestroyitL thusinsuring 'the' dependable rop` eration ofthe iirearm. y y What is claimed is: v

- gage said ringfmeansjtorfmove; said ringmeans y f electricr primer of a' cartridge;l a rsource of elec- Instead of the inductionfiring circuit shown,y

y f it` Willbeunderstood that othertypesof circuits may? lbe' usedgsuch as.y the` capacitative circuit,y

shown in` Fig. 5,which depends; upon the: dis- /tric'al energy;y vmeans'to resiliently'support' ysaid f terminals in said receiver;y and a conductor carchargeoiia 'condensery G charged to 'a high D. C.

f voltageby Ia dynamotorMf In; this case,y the ter 'minalblade -'!,"-and`its mountingy blocky El.' is not*` c f u. sed;.tl1eA circuitbeingfa one-vviresystemground.-r

ed: to the ,sumk frame.

f f The operation of thenifafm' my be sum;

marized .as follows:

@Following rthe]discharge of atcartridge. the

f c powder gas acting'on; the moyableelement Idand` i ijtsmember la; moves. the-flatterr rearwardly ini'y n tiating; therearward,displacementyof the slides `|51 f and Ilrelativetothe vbolt.l Thisinitial rearward m0,.vementI of; theslidesucarriesathe electric firing;

K l means l '1g including'thecontact; pin;` 2.9; rearwardly f in? the bolt. Simultaneously;theconductor fllis ,y withdrawnffrom engagement W'ith'the 'blade' H o, ot, ,they secondary terrrlinawlff andthe .terminal y bladefli'lofy the lprimary coil; enters: the reliefy f yg'lfzove '621' in thel .adjacent Wall 0i,` the slide 16j, ythereby breakingv thefground'fconnection of the primary coil. Further; the locking pawl 2111 is elevatedand unlocksthe bolt whereupon the bolt and slides; are locked together and; moved' rearvvfardlyI in the receiver. Ther red cartridge is ejectedand a new cartridge fed into `thereceiver in; the `usualmanner whereupon the bolt'is moved forwardly bythe action springZLlrinto firing position; When the` bolt, reaches firing position, its forward movement isstoppecl but. theslides I 5 and 1.6i urged-5 by their inertia and the force of. the compression springs. 22:` and 212: continue to move forwardly relatively to the bolt so` as to carryV the contact pin. 2S! into engagement with the electric primer: p.y Since the contact pinis resiliently mounted; itfwill not' strike the-primer with a force comparable to that of the usual;` percussion firearmi With the forward: movement of the slides l5 andV into bolt locking position, the secondary terminal. 7.7: on the right-hand side of the receiver makes contact Withthe conductor lill of'the righthand slide` I5 and immediately thereafter the left-hand terminal blade; 'Ill ridesv out of.' theV reliefgrc-ove 621m thelslide lGiand'engagesthepwall thereof toground.- the.` primary coil 8 8 oft the transformer T, whereupon current builds up in the primary coil inducingy ahigh voltage charge in the secondary coil Which; is carried by the conductor 64. tothe contact Din` 29 and from thence to thel electricprimer to rethe cartridge.

Among the more important novel features oi thea improved electric. bolt oi thisl invention, are its.4 rugged construction,dependability under ex, tre-mely adverse ring conditions, long life and interchangeability with theA usual percussion bolt ot' quick acting, automatic iirearms.V of thel` type relativev to said bolt. into` engagement with; the

ltrical energy; terminails'from said source of'elecried byy onel ofI said, slideelementsarrangedsi, multaneously yto ,engage` one of saidre'siliently.

f mounted; terminals land 'said firing means as` said y V slide` is-move'd' relative to;y said bolt to rdre said cartridge.r

21,Infa frearm for firing cartridges,y having f lcelectriccprimers, a receiverya barrel'seciured to,

, rsaid receiver, breech mechanism comprisingabolt f slidfable in saidreceiverand slides .carried by saidy l bolt, said Slides beingy movable vrelative thereto;

electric firing meanssup,ported in, said bolt; ele-l v lmentson;said' sl'ides.'a1'"rt1.ngedfto;cooperatively'en-y y -V 1 f gage said klringmeans; to move said;iiringrneansr relative to said,bolt.intoengagementwith the elecv tric primer of a cartridgtf an electricalinductlon circuit including. primary and 'secondaryI coils and n y i l 'alsource.ofvoltage;f circuitcljosing I'neans,oper-v atedfbymovement'o' oneoi. said-slides tojcom f plete an.eleotrccircuitincluding the-dsourceof @y n j voltage and saidlprimarycoikand circuitclosing f f 40 means carried, by. the other slide constructed and arranged toV complete a` circuit including said firing means and thesecondary coil immediately succeedingthe closing of the circuit through said primary coil.

3. In. a rearm for rng cartridges having electric primers a receiver, a barrel secured to said receiver, breech mechanism comprising a bolt slidable in said receiver and slides carried by said bolt, said slides being movable relative thereto; electricring means supported in said bolt; elements on` said slides arranged to cooperatively. engage said rlng means toV move said ring means relative to said bolt into. engagement with theI electricprimer of a cartridge; an electricalinduction circuit including primary and secondary coils and asource of Voltage;` a circuit closingv contact mounted onsaid receiverin series electrical circuit with the primary coil and the source of voltage'an actuating surface on, one of said slides constructed and arranged to complete said `circuit through said contact upon movement of said slide relative to-the receiver; and a conductor carried by the other of said slides and arranged to complete` anV electrical circuit including the firing, means and said secondary coil immediately succeeding the closingr of thecircuit includingV said primary coil.

4. In a iirearm for firing cartridges havingA electric primers, a receiver,` a barrel'. secured. to, said receiver, breech mechanism comprising, a bolt slidablein said` receiver,` a slide, carriedby said bolt andmovable relative thereto and a source of electrical energy;` electric firing meamsin` said bolt, said ring means, comprising a body member, v guide bushings mounted.. onl and electrically rl. In flre'arnirfor Aringcartridges having electric primers, a receiver,y a barrel secured; to` f y said receiver, breech mechanism comprisinga, bolt y `slidable in` said receiver and slides, carriedby said bolt,r said. slides being movablerelative thereto;r electric ring meansfsupported in said?. bolt; ele.y c i ments on said'slides arrangedto cooperatively eninsulated from said body member, said bushings having a running t in said bolt, a primer contact pin mounted in said body member, elements on said guide bushings arranged to cooperatively engage said slide to secure said ring means thereto, said slide being arranged to carry said firing means into contact with the electric primer of a cartridge in said barrel; and a conductor carried by said slide and arranged to connect said contact pin to said source of electrical energy.

5. Electric ring means to adapt a rearm having a reciprocable bolt for firing cartridges having electric primers, said ring means comprising a cylindrical element; guide bushings on said cylindrical element, said bushings having a running fit in said bolt to support said cylindrical element therein; a contact pin in said cylindrical element; dielectric members to insulate said cylindrical member and said contact pin from said guide bushings; a contact ring carried by said body member, said ring being in electrical contact with said pin; and dielectric members to insulate said ring from said bushings.

6. Electric firing means to adapt a rearm having a reciprocable bolt for ring cartridges having electric primers, said ring means comprising a cylindrical element; guide bushings at opposite ends of said cylindrical element, said bushings having a running t in said bolt to support said cylindrical element therein; a contact pin supported in said cylindrical element for limited movement therein; a spring in said cylindrical element acting to yieldingly partially extend said contact pin therefrom; dielectric sleeves on said cylindrical element to insulate said cylindrical element and said contact pin from said guide bushings; a contact ring carried by said body member between said bushings, said ring being in electrical 4contact with said yieldable pin; and dielectric washers between the sides of said ring and the adjacent bushings to insulate said ring therefrom.

7. Electric firing means to adapt a rearm having a reciprocable bolt for firing cartridges having electric primers, said firing means comprising' a cylindrical element; guide bushings on said cylindrical element, said bushings having a running t in said bolt to support said cylindrical element therein; a contact pin movably supported in said cylindrical element; a resilient member to yieldingly hold said pin in normal position therein; a stop in said cylindrical member to limit the displacement of said pin from said normal position therein; dielectric members to insulate said cylindrical member and said contact pin from said guide bushings; a contact ring carried by said body member, said ring being in electrical contact with said pin; and dielectric members to insulate said ring from said bushings.

8, In a firearm for ring cartridges having electric primers, a receiver, a barrel secured to said receiver, breech mechanism comprising a bolt reciprocable longitudinally in said receiver to and from breech closing position `and a pair of slides supported on said bolt and movable relative thereto; an electric primer contacting element; means to transmit electrical energy to said primer contacting element comprising a body member mounted in said bolt and arranged to support said contacting element; symmetrical means to support said member in said bolt and to insulate said member from said bolt; a projection integral with each slide arranged to cooperatively engage said symmetrical supporting means at opposite sides thereof; a contact ring on said body member and an electrical conductor mounted in one of said projections 'arranged to engage said contact ring as said bolt moves into breech closing position to energize said electric primer contacting element.

9. In a rearm for firing cartridges having electric primers, a receiver, a barrel secured to said receiver, breech mechanism comprising a bolt reciprocable longitudinally in said receiver to and from breech closing position and -a pair of slides supported on said bolt and movable relative thereto; an electric primer contacting element; means to transmit electrical energy to said primer contacting element comprising a body member slidably mounted in said bolt and arranged to support said -contacting element, said body member being slidably mounted by means of symmetrical bushings surrounding said body and provided with means to insulate said element from said bolt; a projection integral with each slide arranged to cooperatively engage said symmetrical bushings Iat opposite sides thereof; an electric terminal mounted in said receiver; a contact ring on said body between and insulated from said bushings; and a conductor mounted in one of said projections and arranged simultaneously to engage said terminal and said symmetrical contact ring as said bolt moves into breech closing position to energize said electric primer contacting element.

JOHN P. CATLIN. PAUL F. DARBY.

REFERENCES CITED The following references are of record in the iile of this patent:

UNITED STATES PATENTS Number Name Date 937,396 Venier Oct. 19, 1909 1,412,252 Martin et al Apr. 11, 1922 1,782,148 Ross Nov. 18, 1930 2,159,127 Birkigt May 25, 1939 FOREIGN PATENTS Number Country Date 75,614 Sweden Oct. 18, 1932

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