US 2425418 A
Description (OCR text may contain errors)
Aug. l2, 1947. P. H. B'URDETT ET AL. 2,1(4259'413 AMMUNITION Filed April 18, 1942 Patented Aug. l2,Y 1947 UNITED STATES AMMUNITION Delaware Application April 18, 1942, Serial No. 439,522
(Cl.I102-56) Z Claims. l
This invention relates to ammunition, and particularly to the type of projectile of machine gun caliber adapted 'to ignite or explode upon impact with or after penetration of a target.
Such projectiles comprise a jacket of one of the usual materials, an apertured core partly lling t-he jacket and providing a'space for an explosive or incendiary composition, a' heel closure and a gas check. The type of gas check commonly used, comprises a thin soft metal disk, preferably lead, interposed between the upper surface of the incendiary charge and theheel closLue to prevent any hot powder gas from coming into contact with the active composition. The active or incendiary composition is inserted from the heel in a loose granular condition'.` Inasrnuch as this material does not readily transmit pressure, there may be considerable Variation in the compactnessof the composition' in different parts of the bullet, and, by reason ofthis'as well as inevitable variations in thev quantity which is measured out for insertion in agiven` projectile, the explosive or incendiary composition may not entirely fill the cavity provided therefor.
It is important that no empty space remain between the rear of theexplosive or incendiary charge and the gas check or between the gas check and the heel portion of the projectile for the reason that, as shown by high speed X-ray radiography, the extremely rapid acceleration of the bullet when fired displaces suchcharge to the rear into the empty space- Such displacement takes place with considerable violence, and, since the charge is designed to ignite or explode upon impact, the force of its impact with the heel portion of the projectile may be suicient to explode or ignite it prematurely. The acceleration of theV bullet and resulting displacement ofthe charge takes place Yduring the passage of the projectile through the gun lbarrelwherea premature explosion is not desired and may be quite disastrous- Under quantity productiorrconditions it is quite impractical, in view of the variable factors invclved, to ll the-apertured cores to consistently bring the base Aor heel surface of each explosive or incendiary charge to apredetermined level in the core so that'no space will be left between the heel surface of the charge and the gas check or between thegas check andthe heel closure of the projectile. Thisis particularly true when the heel closure is substantially a rigid element of predetermined dimensions.
The object of the present invention is to provide a safe and satisfactory heel construction for incendiary and explosive projectiles which will compensate for variations in the location of the heel surface of the charge and insure that no empty space remains at the rear thereof. A further object is to provide a heel construction which comprises an effective gas check. The invention likewise contemplates other improvements in the construction of such projectiles as will hereinafter more fully appear.
In the drawings:
Fig. l is a sectional view of an incendiary projectile embodying the invention.
Fig. 2 is a fragmentary sectional View of the end portion of a projectile at one stage in its assembly.
Fig. 3 is a fragmentary sectional elevation of the heel portion of such a projectile in one stage of its assembly.
The projectile comprises a jacket lli of such a material as gilding metal, and a hollow cylindrical core Il of any desired hard metal such as steel. Steel cores, however, have the disadvantage that, due to their comparatively low density, the Weight of the completed projectile is substantially less than the Weight of other projectiles fired from the same arms and there is a corresponding departure intheir trajectory, In order to give the projectile such a'weight and trajectory that it can be iired at a target along with'other projectiles without change of aiming point, the core is preferably made of lead which has been hardened to the desired extentby alloyingr with another element or elements, as for example," antimony. Moreover, such lead alloy cores can be readily formed by extrusion, swaging, casting or other similar flow-forming methods and thus produced more rapidly and cheaply than cores of steel.
As clearly illustrated, the core H is substantially shorter than the jacket, leaving a space in the nose of the bullet in front of the core for the reception of the explosive or incendiary composition I3', which composition likewise substantially charge may be introduced in a plurality of increments which are separately pressed into place. For a typical projectile the charge is divided into two equal increments, the material of each increment being scooped out of a receptacle and dumped into a hopper or funnel device which is applied to the open heel portion of the projectile as it is held uppermost. The charge is then compressed under a pressure between 7000 and 28,000 pounds per square inch. A convenient and satisfactory loading pressure for a typical projectile is 11,000 pounds per square inch, but the composi tion does not transmit pressure Well, and even with accurate control of quantities and pressure there is considerable Variation in the resulting volume, and hence in the position oi' the surface of the compacted charge in the core aperture. Theoretically, the charge should exactly fill the core aperture, leaving no empty space between the charge and the heel closure, but this desideratum cannot in practice be achieved.
The present invention comprises the discovery that any possibility of a variable space remaining in the heel portion of the core aperture can be consistently eliminated by the use of an inert granular, comminuted or pulverant material. A wide variety of materials are suitable for this purpose. The essential properties are that the material be relatively dry and granular at room temperature and that it coalesce under pressure to such an extent that it will remain in place throughout the operations and handling necessary to complete the projectile. A further desirable property is a low compressiloility, it being desirable that the free surface of the compacted material be substantially iiush with the heel f the core. Among usable materials there may be mentioned clay and similar materials, including pipe clay, kaolin, levigated alumina, and magnesia; starches such as potato starch and dextrine, gums and resins such as gum arabic; powdered metals such as lead, copper and mixtures thereof with other metallic or non-metallic materials; waxes such as the higher alcohols and candelilla wax; non-metallic elements such as sulfur and miscellaneous organic or metal-organic materials such as tannic acid and calcium resinate. Powdered lead, gum arabic and iiowersrof sulfur are particularly desirable due to their low compressibility. Powdered lead and mixtures of powdered lead with such materials as copper or lead or iron oxides or carbonates have the added advantage of a highdensity which has a desirable effect upon the weight and weight distribution. The powdered or granulal material is preferably applied as follows, reference being made to Fig. 2.
Theincendiary or explosive composition i3 Y having been pressed into place, leaving in the heel of the coreaperture l 2 a recessof variable depth, a suitable quantity of the filler material l5,
adapted to coalesce under pressure, is droppedV into the receptacle formed by the open heel portionv of the extending jacket I9. A ,punch l5, of the same contour and slightly largervthan the core aperture I2, is 'then applied and brought to Y the position Yof the core heel i4, Vcornpacting and coalescing the loose ller material into therrecess f in the rear of the charge I3 and leaving its free surface ilush with the surface i4. The punch is then withdrawn and the excess of ller material lying loosely in the open end is removed.
'Ihe heel of the bullet may be closed in any desired manner as, for example, by inserting a suitable disk of lead into the open end of the jacket and swaging the extending heel portion thereof over such disk.
To insure against forward displacement of the core Il relative to the jacket I0, and the possibility of premature explosion under ring pressure, a disk of a harder metal, such as steel, as well as a lead disk, may be utilized. Such a construction in process of assembly is shown in Fig. 3. Thecharge covering body l5 of filler material has been pressed into place with its free surface ush with the surface i4. A steel disk l1 is placed upon this surface and a lead disk I8 super-posed upon the steel disk. A die IS of suitable configuration is then applied to turn the end of the jacket I0 inwardly and distort the lead 'disk I8 to bring its exterior surface substantially flush with the exterior surface of the ineturned portion of the jacket. The finished construction is shown in section in Fig. 1.
Variations in the precise construction, compositions, loading pressures, etc., which have been illustrated and described may be made, all 'within the scope of the appended claims.
- What is claimed is:
1, A projectile comprising a jacket, a hollow core, a charge of granular diicultly compactible combustible material pressed into and incompletely filling said core, a body of inert pulverant material of low compressibility adapted to coalesce under pressure compacted on said combustible material within and completely filling said core to rigidly secure said combustible material in place therein, and a heel closuresecured in said jacket in abutting relation to said core and said body of inert material.
2. A projectile comprising a jacket, a hollow core, a combustible composition within said core, a gas check comprising a body of coalesced inert granular material superposed on said charge and terminating flush with the end of said core, and a heel closure comprising a steel 'disk and a superposed disk of softer material.
PHILIP H. BURDETT. JOSEPH H. HODGSON.
REFERENCES CTED The following references are of record in the file of this patent:
UNITED STATES PATENTS VNumber Name Date 2,115,047 Stevenson Apr.'26, 1938 1,326,494 Gowdy Dec- 30, 1919 1,567,267 Hitt Dec. 29, 1925 1,299,217Y Pain Apr. 1, 1919 1,453,933 Gibbons et al. May l, 1923 1,074,263 vlssler Sept. 30, 1913 2,129,508Y Slusser Sept. 6, 1938 2,345,619 Moore Apr. 4, 1944 939,966 Baekland Nov. 16, 1909 v958,997 Dunton May 24, 1910 "978,617 Mitats Dec. 13, 1910 17,141,134 Metzner June l, 1915 V1,599,084 Gibson Sept. '7, 1926 FOREIGN PATENTS Number Country Date v132,640 Switzerland July 1, 1929