US2616371A - Cartridge and method of manufacturing same - Google Patents

Description

Nov. 4, 1952 R. r. CATLIN 2,616,371

CARTRIDGE AND METHOD OF MANUFACTURING SAME Filed April 8, 1950 2 SHEETSSHEET l INVENTOR.

ROBERT I CATL/A/ ATTORNEYS Nov. 4, 1952 R. T. CATLIN 2,616,371

CARTRIDGE AND METHOD OF MANUFACTURING SAME Filed April 8. 1950 2 SHEETS-SHEET 2 INVENTOR. Roe/Serf CATL/IV BY H.

Patented Nov. 4, 1952' CARTRIDGE AND METHOD OFMANU- FACTURING SAME :Robert T. Catlin, Stratford,-Conn.,:assignorto Remington Arms Company, --Inc,, Bridgeport- Conn., a corporation of Delaware Application AprilS, 1950, Seria1 No. 1541814 7 Claims.

'This invention relates to a cartridge having a jacketed or composite bullet and to an improved method of assembling same.

The conventional method of forming a jacketedbullet has been to blank and cup from sheet copper or gilding metal stock and by successive draws'to shape the jacket. A lead core is then inserted'in the jacket and the assembly swaged to'the desired form in suitable dies. The multiplicity of operations makes the cost of such bullets 'quite high and such bullets must necessarily be eliminated from consideration in efforts to increase the power and velocity of such large production lead bullet items as caliber .22 long rifle. v

WhenJan attempt is made to drive a lead bullet at a substantially higher velocity than 1500 feet per second, many problems are encountered. Because of the friction with the barrel and the high pressure'and temperature of the propelling gases, lead has a tendency to be deposited onthe rifling, causing the condition knownas leading. Leading interferes with accuracy and is difiicult to remove by ordinary cleaning methods. The passage of subsequent lead bullets will not scour out such deposits and, instead, adds to the accumulation. Further, "leading tends to prevent ordinary cleaning methods from penetrating into bore irregularities or minute pits and thus encourages further attack .by atmospheric moisture and other corrosive agents upon these areas. Attempts have been made to solve these problems by electro-plating lead bullets with copper, cadmium, and other materials but the fragile nature .of 'platings so deposited has tended to prevent the accomplishment of thedesired objective.

It is the object of this invention to produce'a cartridgeloaded with a jacketed bullet suitable for use "under conditions Where ordinary lead bullets are not-suitablafor example, at velocities in excess of 1500 feet per second,.at a cost not substantially greater than the cost of present lead bullet cartridges.

It is contemplated that this object can be attained by the use of substantially conventional lead bullets which are deeply seated in cartridge cases of greater conventional length. By the application of suitable crimping procedures, the

forward portion of the cartridge case may be shaped into a bullet jacket and either partially or completely severed from the remainder of the cartridge case.

The exact nature of the invention as well as other objects and advantages-thereof will become .2 apparent upon consideration of thefollowing specification referring to "the accompanying drawings, ln'whic'h Fig. 1 is an elevational view, partially in section, of "a loaded cartridge embodying the in- 'vention.

Fig. 2 is'a similar view of 'a modified form of such a cartridge.

Fig. 3 is a similar view of another modified form of sucha'cartridge.

Fig. 4 is "asimilar view of a third modification.

Fig. 5 is a partial plan view of an arrangement which'maybe usedfo'r crimping and severing' the jacket.

Fig. 6 is an enlar'ged'view of 'a portion of Fig. 5.

Referring to the drawings by characters of reference, it may beseen that Fig. 1 illustrates a loaded cartridge comprising a cartridge case I crimped to the heel 2 'of a lead bullet 3. Forward of the mouth of the cartridge case the bullet is provided with a jacket 4 crimped into the bullet in one or "more annular bands 5. The jacket is of the'same material as the cartridge case and preferably is formed therefrom by first inserting the bullet into an elongated loaded cartridge case, spinning in the bands 5 and then, by any suitable means, at least partially severing the cartridgecase from the jacket portion and crimping the mouth "of the case into the bullet as 'at6.

In the embodiment of my invention shown in Fig.2, the lead bullet core l is more nearly completely encased by the forward section 8 of the cartridge case 9. .In this modification also, the section! is spun intothe core in several annular bands Land substantially opposite the heel ll of the core 1 a 60 V-notch l2 reduces the thickness of the case wall to one half or less of its original thickness. A notch .005" deephas been found satisfactory with a brass case having a wall .007" thick. Upon firing of the cartridge, the case will separate cleanly at the notched portion, providing a substantially conventional metal jacketed mushrooming bullet. The nose section of the jacket has been rolled in to follow the contour of the bullet, leaving only a soft lead point 13 exposed. Obviously, any desired section of the bullet may be so jacketed, including, at one extreme, coverage only of the rifllng engaging portion and, at the other extreme, substantially complete coverage of the point 'of the lead core. It should also be obvious that, if desired, the exposed lead nose-or some portion thereof may be hollow to enhance the mushrooming eifect.

This modification has one important advantage over the others shown, in that the powder and primer are more perfectly protected from atmospheric moisture and other deteriorating agencies. Such agencies occasionally penetrate beyond the conventional crimps in spite of the attempts to crimp tightly and to additionally seal the joint with the waxlike bullet lubricant which may itself tend to creep through the joint when the cartridges are stored in hot climates.

The modification shown in Fig. 3 includes a target bullet of the so-called wad-cutter type which, by reason of the sharp hard shoulder 14, will cut a clean full diameter hole in a target without the tearing and fraying characteristic of the pointed bullets. This facilitates scoring the targets in match shooting and generally results in slightly higher scores, since a shot which cuts a scoring ring on a target is scored as having the higher value. This cartridge, like the Fig. 1 modification, includes a core I5, and a jacket I 6 formed from the mouth end of an elongated cartridge case I! which has been cut and crimped into the core at I 8.

The embodiment shown in Fig. 4 differs from those previously discussed, in that a gas check 24 of copper, gilding metal, or other suitable metallic or non-metallic material was applied to the lead bullet 25 prior to insertion in the cartridge case 26. The gas check allows the development of higher velocities since it protects the lead bullet from the hot propellent gases. As in the modification previously discussed, the cartridge case 26 may be secured to the bullet 25 by rolling in one or more annular crimps 27 and obviously may be carried out onto the ogival portion of the bullet, as in Fig. 2. The parting line in this modification is established by rolling a sharp annular crimp 2B in the wall of the cartridge case immediately behind the heel of the bullet and the gas check 24. Since the cartridge case is relatively unsupported in this region, it will deform rather than out through, thus crimping the portion which forms a jacket into close engagement with the gas check. As almost all of the cartridge case materials are subject to severe work hardening, the effect of rolling in such a crimp will be to embrittle the bottom of the groove and promote a clean sharp separation. A crimp has been rolled in in this way with a 60 degree included angle symmetrical edge to a depth of about .007 inch where the case wall thickness was originally about .007 inch. The combined efiect of thinning and embrittlement will produce separations at remarkably consistent values of bullet pull and without requiring elaborate control techniques. The machined cut l2 shown in Fig. 2 must be very carefully controlled in depth and, even when so controlled, does not permit the same degree of reproducibility in bullet pull which, of course, has an important efiect on the ballistic performance of progressive burning powders.

Cartridges prepared in this way may be fired at high velocities without causing troublesome leading, since the area of the lead core subjected to frictional contact with the rifling is greatly reduced and. in several modifications, entirely eliminated. To the extent that the bore of the rifle should be fouled on firing, the relatively hard jacket material with the sharp edges present-ed at the annular bands will scrape the bore clean of residue left by the preceding shot. When such bullets are used with non-corrosive primers and non-corrosive powders, it is not necessary to clean the rifle to enjoy long barrel life and consistent accuracy. Obviously, the annularly 4 grooved bullets may be lubricated in the way conyentional with lead bullets with much better results than the conventional smooth jacketed bullet.

The jackets of the bullets of these cartridges, having been formed from the material of the cartridge case, are necessarily thinner than the more conventional jacket material and are therefore relatively easily engraved by the rifling. Hence, particularly if well lubricated, there is little tendency for the jackets, which may be brass, copper, steel, plated steel, or other convenient cartridge case material, to deposit metallic fouling on the rifling. Upon impact, the jacket deforms less readily than the lead, with the result that the exposed lead point is upset in the familiar and highly destructive mushroom form.

Caliber .22 rimfire cartridges conforming to those described above have fired at velocities in the neighborhood of 2,000 feet per second with excellent accuracy and without detriment to continued accuracy as the result of the deposit of lead or other forms of fouling. Other calibers have also been tested with similar results.

In manufacturing these cartridges, as pointed out above, it is desirable to start with an elongated, primed case, a rimfire case being most economical, which is then charged with powder. A substantially conventional lead bullet is then seated in the case in the usual manner, in the position relative to the head of the cartridge case which it would occupy in a normal length case.

The cartridge may then be secured in a suitable collet and the portion of the cartridge case mouth which is to form the bullet jacket rolled or spun down to follow the contour of the ogive. The grooves which crimp the jacket to the lead core may then be spun in and, lastly, the cartridge case may be partially or completely severed from the jacket material. Experimentally, these operations have been performed successively in a lathe type machine using a conventional 60 threading tool or a rotating knife to nearly cut through for the form shown in Fig. 2 and using a circular knife rotated by engagement with the cartridge case to effect a cut and crimp as shown in Figs. 1 and 3.

In semi-production operations, it has been found practicable to use a lathe type machine in which the loaded cartridges are fed automatically one after the other to a collet chuck [9. While the cartridge is rotating with the chuck, as shown in Fig. 5, a backing roll 20 is brought into position to support the body of the case and a freely rotatable crimping wheel 2| is slowly fed into the cartridge. As shown in more detail in Fig. 6, the crimping wheel is provided with one or more circumferential ribs 22 which crimp the jacket into the core and with a knife edge 23 which cuts nearly or completely through the wall of the case and crimps the mouth of the cartridge case portion into the bullet.

For producing the form of cartridge shown in Fig. 4, a similar arrangement has been employed with the sharp edge 23 appropriately located opposite the heel of the bullet and preferably formed with both faces beveled to produce a symmetrical crimp in the unsupported case material.

For full scale operations, the rolling and partial or complete severing of the wall may be effected in conventional crimping machines of the type shown in United States Patents Nos. 237,480 and 310,306, such machines being in practically umversal use in the industry. In this type of machine, a crimping wheel rotates about a. vertical axis and at least a portion of its rim is opposed by a shoe eccentrically disposed by a slight amount and spaced from the wheel by an amount such that a cartridge case may be received between wheel and segment and will be rolled through the gap.

Either the segment or the wheel, or both, may be provided with ribs or knife edges which will perform the necessary rolling and cutting. In the case of the nearly full jackets, as shown in Fig. 2, it is preferable to use two crimping units of this type successively, utilizing one to roll the jacket to match the bullet contour and to commence forming the grooves, and using the second unit to complete forming the grooves and to cut and crimp.

As an alternative method for semi or full production operations, it may be found practicable to use a modified tool corresponding generally to the teachings of Patent No. 2,382,401. With suitably shaped working edges on the collet fingers, tools of this type have been successfully used for cutting off cartridge case material for mouth trimmin as well as for crimping operations of the type referred to in the patent.

While I have illustrated and described specifically several types of cartridges and have described several alternative methods of forming same, I do not intend to be limited to those exact forms. For a definition of the limits upon my invention, reference may be had to the following claims:

I claim:

1. A cartridge comprising a primed and charged metallic cartridge case, and a bullet having a substantially cylindrical body secured to and seated heel-first to a substantial depth within the mouth of said metallic case, said metallic case wall being substantially completely severed in a location rearward of the mouth of said case and forward of the heel of said bullet, at least one of the edges of the case wall at said point of substantial severance being crimped into said bullet, the pull required to separate the bullet, together with the mouth portion of said cartridge case from that portion of the cartridge case in the rear of said point of substantial severance being substantially less than the pull required to separate the bullet from the mouth portion of the case, thus leaving a band of the mouth portion of the metallic case attached to and at least partially enclosing said cylindrical body portion after said cartridge is fired.

2. A cartridge as described in claim 1, no substantial portion of the bullet outside said cartridge case being of a diameter equal to or greater than the outside diameter of said cartridge case.

3. A cartridge as described in claim 2, the mouth portion of said cartridge case forward of said point of substantial severance being formed with one or more annular corrugations indented into the body of said bullet.

4. A cartridge as described in claim 3, the forward edge of that portion of the cartridge case to the rear of said point of substantial severance being crimped into the heel of said bullet.

5. A cartridge as described in claim 4, the cylindrical portion of the body of the bullet extending for substantially the full length of the bullet and substantially all of said cylindrical portion being seated within said metallic case, forming a wad cutter bullet with the sharp shoulder thereof reinforced with the front edge of the band formed of the mouth portion of said metallic case.

6. A method of assembling cartridges which comprises the steps of seating a bullet with a substantial portion of the body thereof within a primed and charged cartridge case, deforming at least a portion of the mouth of said cartridge case to secure that portion to said bullet, and operating upon the wall of the cartridge case at a point between the mouth thereof and the heel of the bullet to substantially completely sever said cartridge case wall and to crimp at least one of said substantially severed edges into the heel of said bullet.

'7. A method as described in claim 6, said deforming step including an operation producing one or more circumferentially continuous annular corrugations in the wall of the mouth portion of said cartridge case indented into the body of said bullet.

ROBERT T. CATLIN.

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

UNITED STATES PATENTS Number Name Date 237,480 Burns Feb. 8, 1881 255,878 McGee Apr. 4, 1882 FOREIGN PATENTS Number Country Date 5.96.563 Germany May 5, 1934;

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