US 2398287 A
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Description (OCR text may contain errors)
April 9, 1946'.
L. D. cHRlsTn-z INCENDIARY BULLETv Filed May l, 194-2 Patented pr.-9, 1946 INCENDIARY BULLET .Lewis D. Christie, Bridgeport, Conn., assignor to Remington Arms Company, Inc., Bridgeport, Conn., a corporation of Delaware Application May 1, 1942, Serial No. 441,266 I 2 Claims. (Cl. 102-90) This invention relates to ammunition and particularly to that type of incendiary bullet, of machine gun caliber, adapted to penetrate the fuel tanks of an airplane and to ignite the gasoline.
The requisites-of an incendiary bullet suitable for this express purpose are exacting. When such bullets are red from the preferred position of attack, that is to say, on the enemys tail, the bullet must penetrate the wing structure including the flap surfaces, flap web, rear spar web and possibly other structural members, before reaching the gasoline tanks. Hence, to be effective, it is essential that the sensitivity of the bullet to impact be Within a relatively limited range so that the maximum flame will develop at the moment the bullet enters the gasoline tank. Furthermore, it is desirable that such bullets shall perform consistently.
Incendiary bullets of this general type are shown in a co-pending application, Serial Number 439,522, led April 18, 1942, which discloses a bullet comprising a jacket having a hollow nose portion, an apertured core, an incendiary composition lling both the hollow nose of the jacket and aperture of the core and a suitable heel closure. It is an object of this invention to provide an improved incendiary projectile` constructed and arranged to produce a maximum flame within a predetermined distance after striking the target. A further object is to provide a jacketed incendiary projectile having ignition means in thenose thereof for positively igniting the incendiary composition at'the moment of impact. The ,invention likewise contemplates other im provenients in the construction of such bullets which will hereinafter be more fully apparent.
In the drawing:
Fig.` 1 is a sectional view of an incendiary projectile embodying the invention.
Fig. 2 Vis an enlarged sectional view of the bulwall thinned adjacent the nose portion II, and
terminating in a solid body of metal at the tip I2. The jacket is provided with a core I3 consisting of a hard metal such as steel or a suitable hard alloy, having an aperture I4. The core is shorter than the jacket so as to leave a space both in the nose portion and heel portion of the jacket. The space in the heel portion of the jacket is provided for a suitable heel closure which, for example, may consistsimply of a lead disc or the combination of a lead disc I5 and a steel disc I6, as shown in Fig. 1, held in position by crimping or turning over the end of the jacket as at I1. The heel closure may also include' an inert powdered material suchas lead or amixture of lead and iron oxide as indicated at I8, which is pressed into the heel end of, the core aperture I4 to prevent set-back. of the incendiary composition and to effect or assist in sealing the incendiary composition I9 against exposurev t0 the powder flame.
TheA aperture I4 ,or the core is suhstantiallir filled with an incendiary composition I9, such as a mixture of powdered magnesium aluminum alloy and barium nitrate in substantially equal proportions. This composition is preferably loaded into the core aperture in two or more increments, the relative size of the increments being susceptible to considerable variation. In accordance with a preferred procedure two increments of charge are used, the first being somewhat larger than the second. Each increment is subjected to a pressurewhich preferably is not less than about 7000 pounds persquare inch,
and may be as high as about 28,000 pounds per' square inch. Although the particular loading technique described has been found to effect very satisfactory performance it will be understood that variations thereof maybe made within the scope of the invention. A
Referring to Fig. 1, the end of the core adjacent the nose portion of the jacket is provided with a counterbore 20 concentric with the core aperture I4 and adapted to receive a cup or capsule arranged to contain a percussion `sensitive priming composition. Any one of many well known powder igniting ammunition priming com positions may be used. A very` convenient cup or container is astandard .22 caliber cartridge case 2|. The latter is supported within the hollow nose portion of the jacket by its open end 22, see Fig. 2, which is seated on the shoulder 23 of the counterbore 20. 'Ihe .22 caliber case is of the rimre type and has a suitable primer composition 21 in its rim 24. The depth of the counterbore may be such that the rim of the case will project forward 'into the hollow nose tion ignites the incendiary composition.
portion of the jacket so as to be adjacent the wall at its thinned portion II and immediately opposite the solid metal tip l2. It will be evident that the .22 caliber case forms, in effect, a closure for the end of the core aperture I4 and consequently when the bullet is charged the incendiary composition I9 substantially lls both the primed case and the aperture of the core. When the bullet is being charged with the incendiary composition it is quite likely that the charging pressures will move the primed case slightly off of the shoulder 23 towards the nose..
of the jacket but such displacement will not be suflicient to free the open end 22 of the casefrom the core aperture. Y
A substantial improvement in the certainty and uniformity of ignition of the incendiary composis loaded the cartridge case. During this process the nose of the bullet is subjected to great pressure which is suiiicient under abnormal conditions to deform the jacket. Hence, if the rim of the primed case were to be positively held in close proximity to the thinned wall portion of the jacket the deformation of the wall might ignite the priming composition. However, by providing the end of the core with a relatively deep counterbore 25 the case will be supported in the position 'shown by the dotted lines, in Fig. 3 only by the compacted incendiary composition and in the event that the nose of the jacket is deformed the fpriined case issubstantially free to move away tion is effected by the use of such a housed prim-'V'v ing composition, which appears to function as follows: When the bullet strikes the target the force of impact causes the wall of the jacket at its thinner portion I I to collapse, as shown in Fig. 2, whereby the solid metal tip I2 telescopes rearwardly engaging the head of the primed case and forcing the case towards and into the core. r)The walls of the vcase are crumpled, and therim -24 of the -case is driven against the end 26 of the core. The rim is then pinched between the end 26 of the core and the solid metal tip I2 of the bullet whereby the priming composition in `the rim is ignited and the ame, heat and pressure of its combus- The primed case thus constitutesfignition means responsive to the force of impact to positively' set re to the incendiary composition. Bullets formed in accordance with this invention have been Vfound to ignite immediately on striking the target and to acquire a maximum ame at a point corresponding approximately to the location of an airplane gas tank withV respect to its usual covering. v
A modification of the bullet is shown in Fig. 3. In this form the counterbore 25 is made of such depth that the .22 caliber case may be assembled charging pressures are suicient to force the primed case up into the hollow nose of the jacket as indicated by the dotted lines.
As in the former case when the bullet strikes the Vtarget the case is forced into the counterbore until the rim of the case is pinched between Vthe end 26 of the core and bullet tip I2, thereby igniting the primer composition and the incendiary composition. In this instance the primed case is partially supported by the compacted incendiary composition in the core and case but ap-V parently the incendiary composition is sufficiently displaced and compressed by the blow to permit the rim of the case to seat on the end 2G of the core as shown in Fig. 4.
This form of the invention is particularly adapted to insure safety when the bullet is being rom .the deformation, thus obviating any likelihood of premature ignition of the priming composition. -It Vwill be understood that the length and contour of the core can be varied to effect any -`desired relationship between the core end, the primed shell and the jacket. Y
Although the use of a .22 caliber case has been shown and described it will be understood that any other priming mixture container may be used, Vand other variations and modifications made within the scope of the appended claims, which claims are to Vbe broadly construed.
W hatis claimed is:
l. An incendiary bullet Comprising a jacket having a body portion and an integral nose portion, said nose portion comprising a solid metal tip joined to said body portion by an area of minimum cross section in said jacket nose; a one-piece core substantially -lling the body portion of said jacket and leaving a hollow nose, said core having an axial aperture extending therethrough; ignition means closing one end of said aperture comprising a primed cartridge case supported within said core aperture and extending into the hollow nose portion of said jacket; an annular recessed shoulder in the `front cf said core constructed and arranged to form a support for the open end Aof said primed cartridge and 'to locate the rim of 'said primed cartridge in proximity to vthe thinned area of said nose; and an incendiary composition iillin'g both the 'aperture of said core and said cartridge case.
2. An incendiary bullet comprising a ljacket having al bo'dy portion and an integral nose portion, said nose portion'comprisng 'a substantially solid tip joined 'at its base to the'body portion of said jacket by a wall section 'of minimum cross section; a core piece in the body portion of said jacket, said core piece having an aperture'and spaced from the base ofsaid tip 'to 4provide said jacket with 4asubstar'itially hollow nose; 'an incendiary 'charge in the aperture of' said core; ignition means for said incendiary Vcharge comprising an impact responsive device; and means to rigidly support said impactre'sponsive device in said hollow nose immediately `be'r'rea'tli thebase of said solid tip and `in proximity to the -wfall -S'ction of minimum cross section whereby on .im-
pact said wall section willv collapse and enable the base of .said solid 'tip to abruptly LEWIsD. CHRISTIE..