US3289588A - Caliber 50 spotting bullets - Google Patents

Description

Dec. 6, 1% A. L. HITCHENS ETAL 3,

CALIBER .50 SPOTTING BULLETS FilGd MELIOh 16, 1954 2 sheets sheet l I NVE N r CIRS Aarun L. Hicchens Henry Lfmunfain Vamun L. D aws nr; Edwar cf DLUWPH Q g x 3% R W A M 1 Q r mswmflaw m UHNEYS.

Dec' 6, 1966 A. 1,. HITCHENS ETAL 3,

CALIBER .50 SPOTTING BULLETS INVENT an s Aar 1:111 L. Hii chm-15 HEnry f1 'Fnuntain. Vern on L D awe. cm. 13 dwar d D -Luwrz States the Army Filed Mar. 16, 1954, Ser. No. 416,724 1 Claim. (til. 102-6il) The present invention relates to a spotting and observing bullet for locating by visual observation the point of impact of the bullet.

More particularly this invention relates to a spotting bullet incorporating in its design suitable arming mechanism allowing absolute safety in handling, and yet maintaining adequate sensitivity after firing.

In co-pending application Serial No. 289,337 by Aaron L. Hitchens, filed May 22, 1952 the effective use of spotting and observing bullets to indicate the position of a target by leaving a visible trace at the point of impact, without at the same time revealing the point of origin of the projectile was discussed. The advantages of the spotted type bullet as a replacement for the tracer type projectile, were also discussed, particularly since a tracer acts as a two way tracking medium to enable enemy personnel to locate the firing arm of the projectile.

In the type of spotter bullet forming the subject matter of the present invention, an important design consideration, in addition to simplicity of structure, is the arming mechanism. A necessary requirement of this mechanism is that it keeps a primer and firing pin axially separated to prevent detonation until impact, and to enable the projectile to withstand reasonably rough handling in storing and in transit. The separation of the primer and firing pin after the projectile has been fired and before impact is also desirable to prevent detonation in mid air, a phenomenon commonly known as in flight functioning. Simplicity of structure of course, is advantageous since it facilitates the manufacture of bullets on mass production basis by suitable and well recognized manufacturing techniques.

It is accordingly an object of this invention to provide a spotter and observing bullet incorporating the above described desirable features.

It is also an object of this invention to provide an arming mechanism for a spotter bullet which maintains the primer and firing pin axially separated during reasonably rough handling, and which is so designed that forces acting on the bullet during firing, or in flight, release restraints separating the primer and firing pin, so that sudden deceleration of the bullet due to grazing or striking of a desired target will detonate the primer.

It is a further object of this invention to provide a spotter bullet containing a smoke producing agent which is pyrophoric upon exposure to air, and which is expelled from the projectile by explosion produced on impact with the target to ignite and to produce a cloud of smoke so as to give a visible trace of the target location.

It is a further and additional object of this invention to provide a projectile made from components which are capable of being produced on a mass production basis by suitable and well recogized manufacturing techniques.

It is yet a further object of this invention to provide a spotting bullet containing a charge of white phosphorus, or other suitable agent for producing clearly visible flash and smoke when exposed to air and which is expelled from the bullet under pressure by a charge of powder which, in turn, is ignited by a primer detonated by contact with a metal projection, or firing pin.

Still another and further object of this invention is to provide a spotting and observing bullet which incorporates into its design a suitable arming mechanism allow- Patented Dec. 6, 1966 ice ing absolute safety in handling and yet maintaining adequate sensitivity after firing.

With these and other objects in view which will become apparent as the following specification develops, reference is made to the accompanying drawing forming a part of the specification and wherein FIGURE 1 is a longitudinal section view of one form of the invention featuring a set-back firing pin.

FIGURE 2 is a longitudinal sectional view of a modification illustrating a diiferential crimp arming mechamsm.

FIGURE 3 is a longitudinal sectional view of still another modification providing a centrifugal arming mechanism.

FIGURE 4 is a transverse section on line 4-4 of the modification illustrated in FIGURE 3.

Referring to the drawings wherein the same reference characters have been used to denote similar or corresponding parts in the several figures for each particular embodiment, FIGURE 1 illustrates a set back firing pin type observer bullet in which reference character 1 designates a hollowed out bullet jacket povided with a forward ogive 2, central cylindrical portion 3 and rearwardly tapering portion 4-. Portion 3 is provided with an external peripheral cannelure 5 into which is crimped the forward end of a cartridge case in the well known manner. Received within and engaging the inner wall of jacket 1 is a forwardly tapering core 7 extending from a point a short distance rearwardly of the nose of the jacket to abut the forward face of a closure plug or cap 8 also engaging the wall of the jacket as at 9 and closing off the rear end of the projectile. Jacket 1 is provided with an inwardly struck flange 10 at its rear end to retain plug 8 securely in place. A lead slug or filler 11 is received within jacket 1 between the point of core 7 and the inner extremity of the jacket at ogive 2, to move the center of gravity of the projectile forwardly to ensure aerodynamic stability of the projectile. Crimp 12 between the inner wall of the jacket and core prevents relative axial movement of the jacket and core.

Core 7 is provided with an elongated axial bore 13 extending from the rear end thereof for almost its entire length and ending in a comparatively short axial bore 14 of smaller diameter. Screw-threaded into the forward end of bore 13 and abutting the shoulder 13a between bores 13 and 14 is a brass plug 15 having a bore 16 in axial alinement with bore 14 and having its rear end closed off by a brass diaphragm 17 integral with plug 15.

An inertia weight 18 occupies substantially the remainder of bore 13, the length of the weight being such as to normally provide axial spaces 1) and 19a between cap 8 and weight 18 and between weight 18 and diaphragm 17 respectively. An annular clearance 20 is provided between contiguous walls of bore 13 and weight 18 to permit free axial movement of the weight relative to core 7 during firing and at impact of the projectile. The rearward half of weight 18 is provided with an axial bore 21 of substantial diameter ending in a centrally located transverse wall or partition 22 separating bore 21 from a second forward axial bore 23 of diameter slightly smaller than bore 21 and extending forwardly almost to the forward end of inertia weight 18. A third axial bore 24 of slightly greater diameter than bore 23 extends from the forward end of bore 23 to the forward end of weight 18.

Bore 24 is occupied by an impact sensitive primer capsule 25, there being an explosive charge 26 received in bore 23, while bore 21 is occupied by a charge of white phosphorous 27, or other suitable agent for producing a clearly visible flash or smoke when exposed to air. A cylindrical plug 28 is received in bore 14 and extends for a short distance into bore 16, and integral with plug 28 is a rearwardly directed firing pin 29 which normally extends almost to brass diaphragm 17. As can be seen in FIGURE 1 a clearance 30 is provided between plug 28 and the wall of bore 14 to permit axial movement of the firing pin upon set back. A transverse retainer washer 31 having an axial flash hole 32 separates primer capsule 25 from explosive charge 26, and an aluminum washer 33 is provided to seal off the rear end of bore 21.

The principle of operation of the device in FIGURE 1 is readily apparent. On set back the point of the firing pin pierces diaphragm 17, thus exposing the firing pin to contact with primer 25. Inertia weight 18 also sets back on firing, thus insuring that primer 25 remains clear of the firing pin while the projectile is in flight. On impact the inertia weight 18 moves forwardly, while the firing pin, locked in firing position on diaphragm 17, remains in rearward position. The forwardly moving inertia weight brings prirner 25 into forcible contact with the firing pin causing ignition. If the firing pin should, on impact, free itself from the diaphragm and thus not remain in rearward position, the jagged edges of the broken diaphragm serve to set ofi the primer, which in turn ignites explosive charge 26. The resulting pressure fractures the jacket and opens the rear of the bullet to eject the white phosphorus and expose it to air whereupon it immediately gives off flash and smoke to give to the operator of the firing arm a visible indication of the point of impact of the bullet.

The modification of FIGURE 2 is based on a differential crimp arming method that requires a substantially greater force to move the inertia weight forward than rearward when the assembly is unarmed. After arming, the force required to move the inertia weight forward is negligible. Essentially the design comprises a hollowed out bullet jacket 40 having a forward ogive 41 merging with a rearwardly extending cylindrical portion 42 with its rearmost edge struck inwardly as at 43 to retain in place a cylindrical closure plug 44. As in FIGURE 1 the functioning parts of the bullet are assembled into a steel core, which may be made as one piece, but which in the modification illustrated comprises a rearward or tail portion 45 abutting a forward surface on closure plug 44 and extending forwardly for approximately one third the length of the projectile, and a forward portion 46 abutting the forward wall of portion 45 at its rear end and having a nose portion tapering forwardly to within a short distance of the inner wall of ogive 41 as at 47. A lead filler plug 48 occupies the space provided between core nose 47 and the inner wall of ogive 41, while jacket 42 is provided with a cannelure 49 to receive the crimped over edges of a cartridge case in the well known manner, there being a corresponding groove or cannelure 51 in core 46 to be engaged by the inner surface of cannelure 49 wherefore jacket 42 and forward core portion 46 are locked against relative axial displacement.

Core portion 45 is provided with an axial bore 51 of substantial diameter extending between closure plug 44 and a forward transverse wall 52 integral with core portion 45, there being an aluminum capsule 53 containing white phosphorus 54 occupying the rear two-thirds portion of bore 51, and a burster and expelling charge 55 in the remaining portion extending to transverse Wall 52, which in turn is provided with central flash passage 56. A suitable seal or washer 57 between white phosphorus charge 54 and expelling charge 55 isolates one from the other in the well known manner.

The arming mechanism per se is located entirely within the forward core portion 46, which is provided with a rear axial bore 59 extending for approximately two-thirds the length of the core, and of the same diameter and in axial alinement with bore 51 in rear core portion 45, and a narrower forward bore 60 extending from a shoulder 61, formed by the terminus of bore 59, to the rear face of nose 47. A tubular inner case 62 of soft steel, or the like, is received within bore 59 with its rear edge abutting transverse wall 52, its forward edge abutting shoulder 61 and with its inner surface in axial alinement with the face 'of bore 60, and slidable within the bore formed by inner core 62 and bore 60 is an inertia weight 63 with its rear face axially spaced from transverse wall 52 to leave a space 64, and its forward edge axially spaced from the rear face of nose 47 to leave a space 65. Inertia weight 63 comprises a forward portion 66 having a slight forward taper, a central cylindrical portion 67 providing a narrow annular space 68 between it and the face of inner core 62, and a reduced rearward cylindrical portion 69. The inertia weight is also provided rearwardly with a first elongated axial bore 70 for receiving a powder charge 71, a second comparatively shallow axial bore 72 in the forward end thereof axially spaced from bore '70, for receiving an impact sensitive primer or detonating capsule 73, and an axial flash passage 74 extending between bores 70 and 72. The rearmost edge of bore 70 is closed off by a seal 75 to retain powder charge 71 in place in the well known manner. The rear face of nose 47 is provided with an axially rearwardly extending projection 76 pointed to form a firing pin for engaging and igniting primer 73 when inertia weight 63 slides forwardly on impact. In order to maintain inertia weight 63 in safe position for normal handling, the wall of inner case 62 is scored or weakened at diametrically opposed locations, and the weakened portions forced inwardly to form flap arms or crimps 77 and 78 with their rear ends turned or crimped inwardly as at 753 and to be received in corresponding recesses 81, 82 formed in the outer surface of reduced cylindrical portion 69 of the inertia weight, at the point approximately where it merges with central cylindrical portion 67 of the weight. When flap crimps 79 and 80 are in place, the outer rear edge or corner of each recess 81, 82 abuts an angularly disposed rear face 83, 84 formed respectively in flap crimp ends 79 and 89 such that inertia weight 63 is prevented from sliding forwardly due to accidental displacement, as when the projectile is roughly handled or jarred. Of course the crimped ends of each flap arm are made strong enough to withstand ordinary rough handling, and lateral displacement or distortion except when acted upon by the forces set up when the projectile is fired. In safe position primer 73 and firing pin 76 are axially separated.

The operation of the differential crimp spotter bullet is as follows. As soon as the projectile is fired the forces of set back cause inertia weight 63 to move rearwardly thereby laterally distorting flap crimps 79, 80 and displacing them outwardly so that upon impact the inertia weight is free to move forwardly to force primer 73 into contact with firing pin 76. When primer 73 ignites, the flash travels by way of flash passage 74 to detonate powder charge 71 which in turn is detonated by way of flash opening 56 in transverse wall 52 to set off expelling charge 55. The explosion of charge 55 fractures the case and at the same time expels the white phosphorus powder 54 which ignites spontaneously upon exposure to air to produce visible flame and smoke.

FIGURES 3 and 4 illustrate a spotting and observing bullet of the centrifugally armed type. The bullet comprises a hollow jacket 101], having a forward ogive 101, a central cylindrical portion 102, merging with a rear boat tail portion 103 having its rear end flanged or struck inwardly, as at 104, to support a closure plug 105. A core 166 received within the hollow jacket comprises a forward nose portion 107 spaced axially rearwardly of the inner forward wall of ogive 101, and a main body portion 108 engaging the wall of jacket and abutting closure plug at its rear end. A lead filler 101 occupies the space between nose 107 and the rear face of ogive 101.

Body portion 1118 of core 166 is provided with diametrically opposed elongated arcuate slots or grooves 110, 111 of substantially depth centrally and with extreme ends gradually lessening in depth, each said groove cooperating with the inner wall of jacket 100 to form spaces or chambers 112, 113 somewhat elliptical in cross-section as seen in FIGURE 4.

Core 106 is provided with an elongated axial bore 114 of substantial diameter extending from the forward face of closure plug 105 to a point or firing pin 115 formed as a rearwardly tapering axial projection of the rear face of core nose 107 and spaced axially a short distance rearwardly of the forward extremity of nose 107. A stepped inertia weight 116 slidable in bore 114 comprises a rear portion 117 of larger diameter extending approximately two-thirds its length, and a forward reduced portion 118, the total length of said inertia weight being such as to provide an axial space 119 between its rear surface and closure plug 105 and an axial offset distance 120 between its forwa-rdsurface and the point of firing pin 115, when the inertia weight is locked in safe position.

Rear portion 117 of the inertia weight is hollowed out coextensive with its entire length to form a space 121 ending forwardly in a transverse wall 122, and in space 121 is received a white phosphorus charge 123. Forwardly of transverse wall 122, the rearward half of the reduced forward end 118 of inertia weight 116 is provided with a first axial bore 124, and forwardly thereof and extending to the forward end of inertia weight 116 there is formed a second axial bore 125 of slightly increased diameter forming with the wall of bore 124, a shoulder 126 peripherally engaging in abutting relation a transverse wall 127. An explosive charge 128 for expelling the white phosphorus when ignited is received in bore 124. Transverse wall 127 is provided centrally with a flash hole 130 in the well known manner.

The centrifugally armed mechanism for the immediately preceding embodiment comprises a pair of diametrically opposed leaf type locking springs, 131, 132 one each received respectively in the forward end of spaces 112 and 113, said springs having their rear ends staked as by studs 133, 134 to the outer wall of core member 106. Springs 131, 132 extend forwardly in spaces 112, 113, adjacent the walls of grooves 110, 111 and are provided at their forward ends with bosses 135, 136 provided with inwardly directed horizontal flanges or looking lugs 137, 138 which extend through diametrically opposed holes 139, 140 formed in core member 108 radially outwardly of transverse wall 122, and with their inner ends engaging the outer wall of reduced portion 118 of inertia weight 116 just forwardly of a shoulder 117a formed between the stepped portions 117 and 118 of the inertia weight.

The operation of this device is essentially similar to the devices illustrated in FIGURES l and 2. When the inertia weight is locked in safe position, offset distance 120 between firing pin 115 and primer 129 is maintained by the abutting engagement of shoulder 117a with locking lugs 137, 138. Although inertia weight 116 is free to move rearwardly without affecting the safe condition of the projectile because of space 119 between closure plug 105 and the rear end of the inertia weight, such action is prevented in handling or in the event the projectile is jarred by a relatively tight engagement between the wall of reduced inertia weight portion 118 and the inner ends of locking lugs 137, 138. Upon set back, when the projectile is fired, inertia weight 116 slides rearwardly until its rear end abuts the forward surface of closure plug 105. As soon as set back ceases, centrifugal force set up by the spinning projectile causes locking lugs 137, 138 to break away from weight portion 118, moving radially outwardly until the bosses 135, 136 engage the inner wall of jacket 100 within spaces 112, 113, thereby freeing the inertia weight for forward movement at impact. During flight of the projectile the inertia weight is prevented from moving forwardly because of the narrow tolerance between its outer wall and the inner wall of bore 114. However upon impact the weight is driven forward until primer 129 engages firing pin 115, and is ignited. The flash in turn detonates explosive charge 128 which explodes to fracture the jacket and open the rear end of the bullet to eject the white phosphorus, which upon coming in contact with the air gives off flash and smoke as previously explained.

The above described illustrations which are intended to be merely exemplary, provide spotting and observing bullets which are simple in design, safe under normal conditions of handling and while in flight, effective for the intended purpose and admirably suited for mass production techniques because of the simplicity in design and the small number of parts or elements. Other modifications and'alt'erations of the above described structures will be apparent to one skilled in the art, and it is obvious that the same may be made without departing from the spirit and scope of the invention as defined in the subjoined claim.

We claim:

A spotting and observing bullet comprising a hollow jacket having a forward ogive, a central cylindrical body portion and a plug closing off the rear end of said jacket, a core in said jacket tightly engaging the inner wall thereof, and having it rear end abutting said plug and its front end tapering forwardly and axially to within a short distance of said forward ogive, there being an axial bore of substantial diameter in said core extending for almost its entire length and ending rearwardly of said forwardly tapering portion, said axial bore having a forwardmost portion of reduced diameter, an insert screw threadedly engaging the wall of said axial bore adjacent said portion of reduced diameter, said insert having a bore in axial alinement with said bore portion of reduced diameter, said insert bore having its rear end closed ofi by a thin metal diaphragm, a firing pin having an enlarged portion slidable within said bore of reduced diameter and a rearwardly directed point extending almost to said thin diaphragm, said firing pin being rearwardly moveable at setback to pierce said diaphragm and expose said point, a setback responsive inertia weight slidable in said axial bore rearwardly of said diaphragm, said inertia weight having a rearward axial bore for receiving a smoke producing agent when expelled into atmosphere and a forward axial bore for receiving an explosive charge detonatable when forcibly engaged by the exposed portion of said firing pin to expel said smoke producing agent into atmosphere, said inertia weight being forwardly slidable at impact to bring said firing pin into engagement with said explosive charge.

References Cited by the Examiner UNITED STATES PATENTS 1,182,488 5/1916 Janney 102-78 1,451,395 4/1923 Hustvedt et a1. 89-1 2,361,955 11/1944 Moore et a1. 10256 2,400,128 5/1946 Moore et a1. 10279 2,480,149 8/1949 Liljegren 10260 X 2,564,870 8/1951 Weiss 10252 2,595,757 5/1952 Brandt 10278 FOREIGN PATENTS 275,822 8/1927 Great Britain.

BENJAMIN A. BORCHELT, Primary Examiner.

SAMUEL BOYD, ARTHUR M. HORTON, Examiners.

S. FEINBERG, W. J. NELSON, W. KUJAWA,

Assistant Examiners.

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