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 
       [0001]    This invention relates to a die for resizing a straight wall cartridge after the cartridge has been fired. 
       BACKGROUND OF THE INVENTION 
       [0002]    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. 
         [0003]    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. 
         [0004]    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 
       [0005]    It is a primary object of the present invention to improve dies for resizing straight wall cartridges. 
         [0006]    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. 
         [0007]    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. 
         [0008]    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. 
         [0009]    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 
         [0010]    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: 
           [0011]      FIG. 1  is a side elevation showing a die embodying the teachings of the invention mounted within a resizing press; 
           [0012]      FIG. 2  is an enlarged perspective view of a side entry cartridge holder utilized in the resizing press shown in  FIG. 1 ; 
           [0013]      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 
           [0014]      FIG. 4  is an enlarged side elevation in partial section showing the construction of a typical straight wall cartridge. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0015]    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. 
         [0016]    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. 
         [0017]    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. 
         [0018]    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. 
         [0019]    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. 
         [0020]    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. 
         [0021]    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. 
         [0022]    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. 
         [0023]    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.