RESIZING DIE FOR SPENT STRAIGHT WALL CARTRIDGES

Abstract

A die for resizing spent straight wall cartridges that is suitable for use in a reloading press. The die contains a pair of spaced apart resizing rings that are arranged to size the bullet chamber of the cartridge casing to a smaller diameter than the charge chamber of the casing to improve the firing performance of the reloaded cartridge.

Description

FIELD OF THE INVENTION BACKGROUND OF THE INVENTION

This invention relates to a die for resizing a straight wall cartridge after the cartridge has been fired.

BACKGROUND OF THE INVENTION

Many gun owners elect to reload their spent cartridges for reuse rather than purchase new cartridges. When fired by a rifle or pistol, the firing pin of the weapon initially strikes the cartridge primer which, in turn, ignites the powder charge that is stored in the rear section of the shell casing adjacent to the primer. The ignited charge generates a high internal pressure within the casing that causes the casing to expand against the firing chamber wall of the weapon while at the same time propelling the bullet contained in the front section of the casing through the barrel of the weapon toward an intended target. After the cartridge has fired and the bullet is expelled, the casing contracts back toward its original size and shape. However, the casing generally cannot completely attain its original configuration. Accordingly, the shell casing must be resized to its original shape prior to reuse and any remaining primer material removed from its primer pocket located at the proximal end of the casing.

Typically, resizing of a shell casing is accomplished by the gun owner using a resizing die that is generally mountable in a hand operated press. The die is typically secured in the stationary head of the press and is axially aligned with a cartridge which is secured in the movable ram of the press with the open end of the casing facing the die. The cartridge is passed into the die wherein the casing surface is reworked to the desired configuration.

Many sportsmen who reload their spent straight wall cartridges employ simple, resizing dies which contains a single resizing ring. One such die is disclosed in U.S. Pat. No. 4,188,855 to Alberts. The Alberts die is designed to be mounted in a resizing press so that the entire casing of a spent cartridge is passed through the single resizing ring of the die. Accordingly, the entire casing of the cartridge is brought to a single uniform diameter. The diameter is generally one which will enable a bullet to be securely press fitted into the open end of the casing. This diameter, however, can produce excessive compression of the charge chamber of the cartridge behind the bullet which adversely effects the fit and thus the performance of the reloaded cartridge when fired from a weapon. In addition, resizing a straight wall cartridge with a single ring oftentimes causes damage to the cartridge casing such that the casing cannot be reloaded. The reason for this is because of the tolerances allowed suppliers of casings and bullets. Cartridge casing suppliers are allowed a rather wide tolerance regarding casing diameters while suppliers of bullets are held to a close tolerance regarding bullet diameters. Manufacturers of single ring resizing dies must thus accommodate the thinnest allowable casing wall thickness. The resizing ring must be small enough to guarantee a sufficient press fit of a bullet in the casing having the smallest allowable wall thickness. This necessitates sizing rings that oftentimes are too small for the main body of the casing.

SUMMARY OF THE INVENTION

It is a primary object of the present invention to improve dies for resizing straight wall cartridges.

It is a further object of the present invention to improve the performance of a spent straight wall cartridges that is reworked in a resizing die.

It is another object of the present invention to provide a relatively inexpensive resizing die for spent straight walled cartridges that is capable of reworking the casing of the spent cartridge to more than one diameter.

A still further object of the present invention is to prevent a straight wall shell cartridge from being damaged when being resized during a reloading procedure.

These and other objects of the present invention are attained by a die for resizing straight wall cartridges that includes an elongated body that can be mounted within a resizing press. The body contains an axially extend bore that passes through the distal and proximal ends of the die body. A first resizing ring is located within the bore at the distal end thereof through which the casing of a straight wall cartridge is introduced into the die. A second resizing ring is mounted in axial alignment with the first resizing ring within the bore at a given distance from the first resizing ring. The inside diameter of the first resizing ring is larger than that of the second ring such that the size of the bullet accepting compartment of the cartridge casing is slightly smaller than that of the charge storing compartment of the cartridge.

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of these and other objects of the present invention reference will be made to the following detailed description of the invention which is to be read in conjunction with the accompanying drawings, wherein:

FIG. 1 is a side elevation showing a die embodying the teachings of the invention mounted within a resizing press;

FIG. 2 is an enlarged perspective view of a side entry cartridge holder utilized in the resizing press shown in FIG. 1;

FIG. 3 is an enlarged side elevation of the die illustrated in FIG. 1 with portions broken away to better illustrate sections of the die; and

FIG. 4 is an enlarged side elevation in partial section showing the construction of a typical straight wall cartridge.

DETAILED DESCRIPTION OF THE INVENTION

For ease of understanding, some components of the illustrated devices will be disclosed as having distal or proximal ends as well as having top, bottom or side surfaces. These terms are meant to be relative and not necessarily limiting. By the same token, the term “straight wall” casing is used herein in the same manner as it is used in the art to distinguish the spent cartridge that is resized in the present die from other cartridges known and used in the art such as bottleneck cartridges and the like.

A typical straight wall cartridge ready for firing is illustrated in FIG. 4. The cartridge, generally references 10, contains a cylindrical shaped casing 11 that is opened at its distal end 12 and is provided with a circular web 13 at its proximal end 14. The web is coaxially aligned with the central axis of the casing and contains a primer 17 which is mounted in the primer pocket with flash hole 18 of the cartridge. The primer is arranged to be actuated by the firing pin of a weapon (not shown) to ignite a charge 15 that is stored in the charge compartment A of the casing. A bullet 19 is press fitted into the bullet compartment B of the casing which is expelled from the casing when the charge is ignited. It has been found through testing that the bullet compartment B and the charge compartment A of straight wall casing should both be worked during the resizing operation to slightly different diameters with the outer diameter of the charge section A being slightly larger than that of the bullet section B. This allows for a tight press fit of the bullet into the casing while at the same time insuring that the charge section is worked into a slightly larger smooth circular configuration which insures that the casing will properly fit and expand into tight sealing contact against the firing chamber, of a weapon when the charge is ignited. Although the difference in the two compartment diameters is relatively small, a marked improvement in the performance of reloaded cartridges produced in this manner has been noted.

Turning now to FIGS. 1 and 3, the resizing die, generally referenced 20, embodying the present invention is shown in greater detail. The die includes an elongated cylindrical body 21 that has a knurled head 23 at its upper proximal end 24. A bore enters the proximal end of the body and passes axially through the body and exits out of the distal end 27 of the body. The outer surface of the body is provided with a male thread 30 that extends along a considerable length of the body. As best illustrated in FIG. 1, the outer male thread 30 is adapted to mate with a female thread in either the stationary head 31 or the movable ram 32 of a resizing press. In this case, the die is shown mounted in the stationary head 31 with the central axis 35 of the die being coaxially aligned with the path of travel 37 of the movable ram. The die is secured in a desired position within the stationary head by means of a lock nut 38 that is mated to the outer threads of the die body and tightened against the upper surface 34 of the stationary head.

A spent cartridge 11 to be resized is shown mounted in an upright position upon the top surface 40 of movable ram 32 with the open distal end of the cartridge casing facing the prepositioned die. The cartridge is shown secured in an upright posture by means of a side entry shell-holder 41 (FIG. 2) of the type commercially available from Redding Reloading Equipment of Cortland, N.Y. under the tradename E-Z Feed. When seated within the shell-holder, the casing 42 of the cartridge is coaxially aligned with the bore of the die body. Actuating the closure mechanism of the press (not shown) will cause the open end of the shell casing to be axially advanced into the bore of the die housing.

With further reference to FIG. 3, a pair of resizing rings are mounted within the bore of the die housing at the distal end 27 of the housing. These resizing rings include a first outer resizing ring 45 and a second inner resizing ring 46. The rings are located within a radially expanded cylindrical retention chamber 48 that is machine to a desired depth within the distal end of the bore. The outside diameter of each resizing ring forms a tight sliding fit with the inner wall of the retention chamber that does not allow for radial movement of the ring within the chamber. In assembly, the inner ring is seated against the rear shoulder 49 of the retention chamber and a cylindrical spacer 50 is placed in abutting contact against the outer face of the inner ring. The inner face of the outer resizing ring is mounted in abutting contact with the distal end of the spacer. The depth of the retention chamber is such that the outer face of the outer ring is positioned just inside the distal entrance to the die body bore when the ring is in abutting contact with the spacer. The ring assembly is secured in place against axial movement by mechanically crimping the rim 51 of the bore entrance against the outer face of the outer resizing ring.

The inside opening 53 of the outer resizing ring is such that the ring will work a casing passing into the die to a first predetermined diameter as the cartridge casing is advanced through the die. The inside opening 54 of the inner resizing ring is such that the inner ring will further resize that portion of the casing that is advanced therethrough to a second smaller diameter. The inside diameter of the spacer is larger than that of the outer ring so that the casing of the cartridge will move freely through the spacer. Preferably, the resizing rings are fabricated of a carbide material, however, depending upon the casing material, hardened steel or other similar materials may also be used without departing from the teachings of the present invention.

The axial location of the two resizing rings within the die bore is preset so that the outer resizing ring will shape the charge chamber of a cartridge to a first predetermined diameter and the second inner resizing ring will shape the bullet chamber to a second slightly smaller diameter when the spent cartridge casing is advanced to its full length into the die body. In this particular case further advancement of the casing is prevented by the shell holder 41 being intercepted by the rim 51 at the entrance to the die bore. Any other type of stop capable of limiting the axial penetration of the cartridge into the die might be used in the practice of the invention. It has been determined that maintaining the inside diameter of the outer resizing ring at between 0.002″ and 0.010″ larger than that of the inside diameter of the inner resizing ring, the performance of a reloaded cartridge produced in the present die is considerably improved when compared to a reloaded cartridge that contains a casing that has been reworked to a single uniform diameter.

The present die is equipped with a decapping unit 60 for removing a spent primer that is housed in the primer pocket of a cartridge as the cartridge casing advanced through the die bore. The decapping unit includes a male threaded shank 65 that is arranged to mate with an internal female threads located in the upper section of the die bore. A decapping rod 66 is attached to the shank and extends downwardly into the die bore. A decapping pin 67 protrudes from the lower end of the rod that is capable of passing through the flash hole of the casing to dislodge the spent primer from the primer pocket. As illustrated in FIG. 3, both the decapping rod and pin are coaxially aligned with the axial centerline 35 of the die bore. The upper end of the shank 65 is provided with an enlarged head 70 to facilitate easy turning of the shank within the die bore to allow the unit to be adjusted within the die body.

While the invention has been described with reference to preferred embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof to adapt to particular situations without departing from the scope of the invention. Therefore, it is intended that the invention not be limited to the particular embodiments disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope and spirit of the appended claims.

Claims

1. A resizing die for producing two separate diameters in a straight wall casing of a spent cartridge that includes:

a die body having a distal end and a proximal end, said die body further including a bore that passes into said die body through an opening in said distal end;

said die body housing an outer resizing ring mounted in said opening at said distal end of said die body;

said die body further housing an inner resizing ring mounted in said bore in axial alignment and at a given distance from said outer resizing ring; and

said outer resizing ring containing a first inside diameter that is larger than a second inside diameter that is contained in said inner resizing ring such that two separate diameters are produced within a casing of a spent straight wall cartridge that is advanced into said die body though said distal wall opening.

2. The die of claim 1, wherein said first inside diameter of said outer resizing ring is between 0.002″ and 0.010″ larger than said second inside diameter of said inner resizing ring.

3. The die of claim 1, wherein each of said resizing rings is fabricated of a carbide material.

4. The die of claim 1, that further includes spacer means within said bore for maintaining said given distance between said resizing rings.

5. The die of claim 1, that further includes means for adjustably mounting said die body within a resizing press.

6. The die of claim 1, that further includes a decapping means adjustably mounted within the bore of said die body for ejecting a primer from said cartridge as said cartridge is advanced through said first and second resizing dies.

7. A die for resizing the casing of a spent straight wall cartridge that includes:

an elongated die body having a distal end and a proximal end, said body further including a bore that passes axially through said body between distal end wall and a proximal end wall;

said bore containing an axially aligned, radially expanded, cylindrical retention chamber having an open entrance at one end thereof that is located in said distal end wall and a radially extended shoulder at its other end;

an inner resizing ring mounted within said retention chamber in abutting contact with said shoulder, said inner resizing ring having a first inside diameter,

a cylindrical spacer having a distal end and a proximal end mounted within said retention chamber with said proximal end of spacer in abutting contact with said inner resizing ring.

an outer resizing ring mounted within said opening of said retention chamber in abutting contact with said distal end of said spacer and having a second inside diameter that is larger than that of said inner resizing ring; and

locking means for maintaining said outer resizing ring within said opening in abutting contact with said spacer.

8. The die of claim 7, wherein said locking means is a crimped rim that surrounds the entrance to said retention chamber which is in abutting contact with said outer resizing ring.

9. The die of claim 7, wherein said inner and outer resizing rings are mounted in a tight sliding relationship with an inside wall of said retention chamber to prevent radial displacement of said resizing rings.

10. The die of claim 9, wherein said cylindrical spacer has an inside diameter that is larger than the inside diameter of said outer resizing ring.

11. The die of claim 7, wherein said resizing rings are fabricated of a carbide material.

12. The die of claim 7, wherein said die further includes means for adjustably mounting said die body within a resizing press.

13. The die of claim 7, that further includes a decapping means mounted within said bore for ejecting a primer from a cartridge that is advanced into said bore through said distal end entrance.

14. The die of claim 7, wherein the inside diameter of said outer resizing ring is between 0.002″ and 0.010″ larger than that of said inner resizing ring.

15. The die of claim 7, wherein said die body is cylindrical and contains a male outer thread that extends along at least a portion of its outer surface whereby said die can be threaded into a die press.