US2193245A - Ammunition - Google Patents

Description

Math 12,194). P. H. BUXTON AMMUNITION Filed Sept. 16, 1936 Patented Mar. 12, 1940 v UNITED STATES PATENT OFFICE Paul a. Bnxton, alum, n1., assignor to Western Cartridge Company, East Alton, Ill.. a corporation of Delaware Application September 16, 19st, sci-n1 n 101,029

'4 Claims. (01. zo-Ls This invention relates generally to ammunition In accordance with the present invention a and particularly to metalliccases as employed in steel is selected which will lend itself to the ammunition. g drawing operations required for the production In ammunition such, for instance, as shot of the ammunition case desired. While in the shells, it is customary to provide a metallic head, specificembodiment to be herein described the usually of brass, into which is fitted and anchored invention will be described in connection with a tube, generally of paper, so as to provide a case the manufacture of shot shells, it is to be underinto which is loaded the propellant and prostood that the features of the invention are also jectile charges together with a suitable primer. applicable to the manufacture of other ammuni- Likewise in ammunition, such as metallic :small Y tion cases, such for instance as metallic small 10 arms'ammunition, a metallic case adapted to arms ammunition cases, both center fire and contain the primer and the propellant charges rim fire as well as to the manufacture of amand connect with the projectile is provided. munition cases for ordnance. Heretofore such cases have generally been made While avariety of steels may be employed for of brass or other copper alloy. .the manufacture of ammunition cases, in ac- 5 The object of the present invention, generally cordance with the present inventiona steel whose stated, is to provide an improved ammunition physical properties are substantially uniform in case and round. I all directions is desirable. For example, the A further object of the present invention is toordinary steel employed by ammunition manuprovide a process of manufacturing ammunition facturers, such as the reenforce in shot shells, cases in which steel may be employed. may be employed for the manufacture of am- A more specific object of this invention is to munition cases where such steel is of a character provide an ammunition case of greater strength such as to permit it to be drawn to a reduction andof less weight than those heretofore emof about fifty percent or more. While a reducployed without sacrificing any of "the advantion of fifty percent is sufllcient for the manu- 25 t ge usfeatures. of the,ammunition cases herefacture of shot shell heads for ordinary shot tofore constructed. shells in which the metallic head heretofore em- Other objects will become apparent t th ployed has been relatively short, those shot shells skilled in the art when the 011:1; description which areprovided with a propellent charge, such is read in connection with the accompanying 88 to Pr h her pr s and hi her V8- 6 drawing w eh ill strates th I i. am; steps in locities of the projectile charge, and in'which the a. process 0 manufacturing ammunition cases in metallic head has customarily been made about accordance with the present invention. long may best be produced from steel whose Figure l is a perspective view of a sheet metal drawing properties permit greater than 50% reblank from which the unition case is fabduction. as an example of the steels which may 'ricated. be employed for the manufacture of ammunition Figure 2 is a perspective view, partbeing in cases such as shot shell heads (short or long) section showing a cup resulting from drawing and small arms ammunition cases (rim fire or operations performed upon the blank of Figure 1. center fire) steels made according to the disclom Figure his a perspective view partly in section sure of the copending application of Norman -P. 40 showing the result of a further deforming op- Goss, serial No. 41,432, filed on or about Septemeration upon the cup 0:? Figure 2. ,ber 20, 1935, may be employed with advantage.

Figure 4 is aview in side elevation of a shot Four examples of such a steel are given in the shell case provided with the metallic head shown following tables showing the analyses thereof, it

in Figure 3. being understood that the balance in each in- 45 Figure 5 is a perspective view-partly in section stance is iron. 1 p showing a loaded shot shell. 7

I31 accordance Wlth the Present m r Carbon Phosphorus Manganese Sulphur Silicon erally stated, ammunition cases are formed of 1 steel having such charactermflcs 93150 Permit Percent Percent Percent Percent Per cent 50- them to withstand deep drawing and deformation. 1 1 I .33 .gg The present invention further contemplates a 3 I10 I013 I43 I024 102 round of ammunition providedwith a steel case, 4 All!) .35 .029 .02

rust proofed in such a manner as to withstand 1; defotion alter the rust proo operation. Each of the steels whose composition is given ir'iigthe foregoing table is characterized by the absence of directional properties, that is to say, the physical properties including tensile strength, yield point, elongation, etc. are substantially the same, regardless of the direction in which the reading is taken. For instance, as shown in the following table, the physical properties in a longitudinal direction are substantially the same as the physical properties in the transverse direc- Since the explosive shock to which an ammunition case is subjected in use is such that adequate strength must be provided in all directions, the use of such non-directional steel has the advantage of permitting the employment of lighter gauge stock than would be required with ordinary steel, without, however, sacrificing safety because the tensile strength of thin nondirectional steel may be greater than the tensile strength in the weaker direction of heavier steel. Although the tensile strength, in the stronger direction of the heavier steel weight exceeds the tensile strength of the non-direction steel such excess tensile strength is of no utility in ammunition cases. Accordingly, the use of such nondirectional steel permits the ammunition cases for a given lead to be made thinner than with directional steel.

In order to' facilitate drawing of the metala plating of a lubricating metal, such as copper, cadmium, zinc, etc., may be applied to the sheets of steel before the drawing operation is begun. Blanks formed of the steel above described, may then be passed through a convenient number of drawing dies so as to cold-draw the blanks to cup shape and finally deform the same to the shape desired for the ammunition case. The thickness of the sheet metal from which the blanks are punched will, of course, depend upon the character of ammunition in which it is to be em- Ployed. In the'case of ordinary shot shells the metal from which the heads may be formed may. for instance, be about .015" thick, while, if the heads are to be employed for high velocity shot shells, heavier gauges, such for instance as .0175" may be employed. In the case of the ordinary shot shells in which short metallic heads are customarily employed reduction of 40%, or even less, is suflicient for the production of suitable heads, while in the case of higher velocity shells where the heads are customarily longer, it is desirable to employ a metal capable of withstanding a reduction of 50 t0,65%.

When a steel which will withstand the reductions above suggested is employed in the manufacture of ammunition cases, the metal may be cold worked through the drawing and deforming operations to produce the desired case without intermediate heat treating, but it will be understood, of course, that after the drawing and deforming operations are completed it is desirable to anneal the case under such conditions as to release the internal strains which havebeen set up therein during the cold working. In the case of the steels mentioned specifically hereinabove, such a strain-relieving anneal may, for example, consist in treating shot shell heads at a temperature of approximately 475 C. for a period of about ten minutes. Such a treatment, while sufllcient to relieve the internal strains in the shot shell heads is, nevertheless, not such a heat treatment as will substantially soften or take the stiffness out of the article produced or any part thereof. This represents an advantageous feature in ammunition cases, such as shot shell heads or center flre metallic ammunition cases, in which there are one or more projections upset in the center of the head which are later to be somewhat deformed so as to snugly engage a battery cup to be inserted therein or anchored with the base wad in a shot shell. In the case of shot shells the prongs which are customarily upset for penetration into the base wad have a stifiness in excess of the stiffness provided by the ordinary brass shot shell head and consequently a more secure anchor with the base wad and adjoining parts is achieved by the use of steel treated as hereinbefore described.

Referring now particularly to the drawings which illustrate the product resulting from the various steps in the process of manufacturing an ammunition case in accordance with the present invention, it will be understood that a sheet of metal, such, for instance, as. the steel hereinbefore specificallydescribed, and having a thickness of .0175" may be provided. Such a sheet of metal may be given a lubricating plating of copper in any suitable manner. Blanks of the desired size may then be stamped from the sheet so as to provide a disc I in the form generally illustrated in Figure 1.

The disc I may then be passed through a series o1 drawing dies in order to fold and draw the disc I to the cup shape illustrated in Figure 2 wherein the article will be provided with a head section 2 and a flange section 3. In the drawing operation the metal in the flange section 3 may be reduced from the initial thiclmess of, for instance .0175" to about .006- at the open end of the cup.

The cup may then be further cold worked with the usual apparatus for forming crimp 4 at the juncture of the head and flange sections of the cup. The head 2 of the cup may then be centrally upset in order to provide the usual prongs 5 extending upwardly on the interior thereof for the purpose of anchoring with the base wad and adjacent parts later to be inserted. The usual knurling and crimping operations may then be performed upon the flange part 3.

The shot shell head thus produced may then be subjected to the annealing treatment, mentioned above, for the purpose of relieving the internal strains in the article, and thereafter may be rust proofed in any suitable manner which will withstand a further deforming operation at the time of heating. For instance, a further plating of a rust proofing metal may be applied thereto, particularly advantageous results being accomplished by theuse of a metal which is electropositive as to iron, such as cadmium or zinc. By the use of metals electropositive to iron, a flrmly adhering plating is accomplished both inside and outside of the head and the head will withstand further deformation to which it is customarily subjected during. the sotions of features may be made without departing customary base wad and a suitable primer inserted, and the crimp l compressed, as shown in Figure 4, by the action of the hunter customarily employed for carrying out this operation. The assembled shell may then be loaded with a propellent charge I and a projectile charge 8 inter.- posed by a suitable wedding 9 so as to form the completed shell.

By the use of steel which is substantially de void of directional properties, as hereinbefore described, ammunition cases having superior strength to similar cases made of copper alloy may be provided and ammunition cases formed .in this manner are particularly preferable for of long use, may have become enlarged to an extent such that an ordinary brass or copper alloy ammunition case might rupture when fired therein. By the use of a steel capable of relatively deep drawing,fas hereinbefore described, and characterized by the fact that its physical propuse in worn guns wherein the chamber, because cities in each direction 'are substantially the same, an ammunition case may be provided in which, without increasing the thickness of the metal and in fact in many cases by reduction of it. higher pressures may be withstood in worn g'un chambers than is possible with the customary copper alloy ammunition cases.

While the present invention has been described with particular reference to its advantages and to the procedure employed in the manufacture of shot shell heads, it is to'be understoodthat the invention is not limited to use in shot shell heads, but that it is of wider applicability since small arms metallic ammunition'cases' may be manufactured in accordance with the present invention with suitable modifications of the tools employed in the manufacture of,the-usual copper alloy cases as by appropriate alteration of tolerance and clearance for the working ofthe diiferent metals. It is to be distinctly understood, therefore, that the present invention is not limited to the precise details of procedure which have hereinbefore been described, but that modiiications may be made therein. and that the use of various individual features and subcombinastrains therein.

from the spirit of the present invention. It is to be understood, therefore, that such modifications and the use of such individual features and subcombinations of features as present them selves to those skilled in the art, although not specifically described herein, are contemplated by and within the scope of the appended claims.

- Having thus described the invention, what is claimed is:

1. In the art of making ammunition cases, the process comprising, providing a disc of steel whose physical properties in all directions are substantially uniform, cold drawing the disc to cup shape without heat treating, puncturing the head of the cup to form prongs, and thereafter annealing the cup 'under conditions such as to relieve the strains therein.

2. In the art of making ammunition cases, the process comprising, providing a disc of steel whose physical properties in all directions'are substantially uniform,v cold drawing the disc to cup shape, upsetting the head of the cup to form a projection on the interior of the cup, and otherwise deforming the cup all without heat treating; and thereafter annealing the cup to an extentsuflicient to relieve the strains therein without substantially softening the metal in th upset'projection. Y

'3. In the art of making ammunition cases, the

1 process comprisin providing a disc of steel whose physical properties in all directions are substantially uniform, cold drawing the disc to cup shape without heat treating, and thereafter annealing the cup under conditions such as to relieve the strains therein.

4. In the art of makingammunition cases,

without heat treating; and thereafter-annealing the cup to an extent suflicient to relieve the PAUL, H. sux'roN.

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