Patent Publication Number: US-6907766-B2

Title: Lip forming tool for firearm magazines

Description:
This application claims the benefit of U.S. Provisional application No. 60/371,024, filed Apr. 9, 2002. 

   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to the field of tools used to modify the magazines of firearms. 
   The use of tools or dies to modify the feed lips of magazines for firearms is known. Firearms magazines are provided with feed lips to hold rounds of ammunition in the magazine and to station the rounds at a proper angle for feeding of the rounds into the chamber by the bolt or slide of the firearm. 
   The feed lips also control the release of the rounds from the magazine. The timing of the release of the round from the magazine is critical to the proper functioning of the firearm. 
   Tools or forming dies have been manufactured to create a consistent release point in the magazines of pistols like the M1911A1. The lips of issue magazines of the M1911A1 are made with a “gradual taper” release configuration. The release of the rounds in these magazines varies considerably and anvil/die tools, such as that manufactured by Novak&#39;s of Parkersburg, W.Va., have been designed to form a consistent point of release at a predetermined point, at the same location, of both feed lips. This consistent release point improves the function of the pistol especially when using the shorter nosed match ammunition used in competition. 
   Some semiautomatic firearms like the M16A4 rifle and M4A1 carbine use aluminum magazines. The aluminum magazines are lighter in weight but are prone to damage from impact to the body of the magazine and deformation of the feed lips. In the case of the M4A1, the short barrel/gas system contributes to increased failure to feed which can be reduced with an increased feed lip angle to allow for a higher presentation of the nose of the round to the chamber for feeding. This increased angle also limits the distortion to the bullet enhancing the accuracy of the firearm. A decreased feed angle, which can be caused by an impact to the feed lips, can increase the frequency of failures to feed due to the rounds impacting the upper receiver below the feed ramp of the barrel extension. 
   2. Discussion of Prior Art 
   The die and anvil tool sets previously mentioned are configured to allow the user to use these tools on magazines having a closed bottom like the magazines of the M1911A1 pistol. The user must insert the anvil from the top of the magazine and place a steel dowel through one of the holes in the side of the magazine to hold the anvil in place. The die is placed over the feed lips and struck with a hammer. The die and anvil come together and form release points in the lips of the magazine. Several attempts may have to be made as the die and anvil are not joined in such a way as to align them during use. 
   It should be clear to the reader that a proper magazine feed lip angle is critical to the proper function of firearms which use a magazine. It should also be clear that a tool that repairs or alters the feed lip angle is necessary to properly maintain/enhance an inventory of magazines. The tool should be configured to properly align the die and anvil during use to minimize the attempts required to complete the process. 
   Objects and Advantages 
   One object of our invention is to provide a tool which will consistently alter/repair the feed lips of magazines to a predetermined angle to improve feeding. The preferred embodiment of the invention will be hardened and have a means of keeping the die and anvil in proper alignment to allow for proper forming of the feed lips with only one attempt. The preferred embodiment will also be easily installed/assembled by the user and will require no additional tools, such as a hammer, to apply the force necessary to form the feed lips. 
   A further object of our invention is to provide a tool that can be configured to fit the inside dimensions of a magazine in such a way that the anvil of the tool will insert from the bottom of the magazine and travel easily to the top of the magazine unless a deformation in the side walls is encountered. The anvil will aid in the detection of deformation of the side walls and will provide a rigid surface with which an armorer, or other user, can utilize a peening hammer/non-marring tool to repair the deformation (dents). 
   Further objects and advantages of our invention will become apparent from a consideration of the drawings and ensuing description. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention will now be described further by way of example, with reference the accompanying drawings, in which: 
       FIG. 1  is a side view of the preferred embodiment disassembled and at either end of a magazine with a partial rear view of the upper portion (die); 
       FIG. 2  is a perspective view of the preferred embodiment. 
   

   REFERENCE NUMERALS IN DRAWINGS 
   
     
       
         
             
             
             
             
             
             
           
             
                 
             
           
          
             
               1 
               handle 
                8a 
               rear alignment 
               15a 
               rear tab 
             
             
                 
                 
                 
               pin 
             
             
               2 
               die 
                8b 
               front alignment 
               15b 
               front tab 
             
             
                 
                 
                 
               pin 
             
             
               3 
               anvil 
                9 
               forming radius 
               16 
               front tab relief 
             
             
               4 
               threaded shaft 
               10 
               front rib relief 
               17 
               through hole 
             
             
               5 
               forward stop 
               11 
               rear rib relief 
               18 
               threaded orifice 
             
             
               6 
               set screw 
               12 
               feed lip 
               19 
               kerf cut 
             
             
               7 
               left forming 
               13 
               magazine body 
               20a 
               rear pin hole 
             
             
                 
               surface 
             
             
               7a 
               right forming 
               14 
               follower stop 
               20b 
               front pin hole 
             
             
                 
               surface 
             
             
                 
             
          
         
       
     
   
   DESCRIPTION OF THE PREFERRED EMBODIMENT—FIGS.  1  AND  2   
     FIG. 1  shows the side view of the preferred embodiment separated and positioned above and below a magazine body  13 . A handle  1  is rotationally joined to a die  2  by a set screw  6 . A rear view of die  2  shows the radii of left forming surface  7   a  and right forming surface  7   b  which are identical to the radius of a magazine feed lip  12  to be altered or repaired. Die  2  is equipped with a forward stop  5  to support die  2  during the forming process. A threaded shaft  4  of handle  1  joins die  2  to an anvil  3  and draws die  2  and anvil  3  together to form feed lip  12 . 
   Anvil  3  is fitted with a rear alignment pin  8   a  and a front alignment pin  8   b  which mate with through holes in die  2  to guide die  2  and anvil  3  and assure proper alignment during the lip forming process. A rear tab relief  11  of anvil  3  provides clearance for a rear tab  15   a  of magazine body  13 . A front rib relief  10  of anvil  3  provides clearance for the front rib of magazine body  13 . A front tab relief  16  provides clearance for a front tab  15   b  of magazine body  13 . Left forming surface  7   a  and aright forming surface  7   b  mate with, and are identical to, the outer radius of feed lip  12  of magazine body  13 . This configuration ensures consistent forming of feed lip  12  when die  2  and anvil  3  are drawn together and prevents the possibility of excessive forming of feed lip  12 . The forward portion of anvil  3  is configured in such a way as to prevent interference of anvil  3  with a follower stop  14  of magazine body  13 . 
     FIG. 2  shows the preferred embodiment joined where rear alignment pin  8   a  and front alignment pin  8   b  protrude through a rear pin hole  20   a  and a front pin hole  20   b  respectively. Threaded shaft  4  of handle  1  rotates within a through hole  17  of die  2  and threaded shaft  4  engages a threaded hole  18  of anvil  3 . Set screw  6  of die  2  engages kerf  19  of handle  1  to rotationally join handle  1  and die  2 . The clockwise rotation of handle  1  draws die  2  and anvil  3  together. The counterclockwise rotation of handle  1  separates die  2  and anvil  3 . Rear alignment pin  8   a  and front alignment pin  8   b  are of a sufficient length to guide die  2  and anvil  3  during the lip forming process but are not long enough to interfere with handle  1  when die  2  and anvil  3  are drawn together to complete the lip forming process. To perform the lip forming task, the user inserts anvil  3  into the base of magazine body  13  (alignment pins first) and inverts magazine body  13  to allow gravity to position anvil  3  feed lip  12  of magazine body  13 . The user then pinches the side walls of magazine body  13  directly over anvil  3  to hold it in position to allow for the joining of threaded shaft  14  and threaded hole  18 . Handle  1  is rotated clockwise drawing die  2  and anvil  3  together to form the magazine feed lips. 
   To further improve the feeding of rounds from the magazine, a modification to the typically straight configuration of the magazine spring is beneficial. Forming of the spring to a radius similar to that of the magazine is necessary. The orientation of the curvature of the spring for assembly is opposite that of the curvature of the magazine. In other words, the more open ends of the coils are oriented towards the front of the magazine. This provides more force to the front of the follower, keeping the nose of the rounds high in the magazine, improving feeding 
   While the description above contains many specificities, these should not be construed as limitations on the scope of the invention, but rather as an exemplification of one preferred embodiment thereof. Many other variations are possible. 
   SUMMARY 
   It should, therefore, be clear to the reader that the structure of our invention will enable individuals to consistently alter or repair the feed lips of magazines to a predetermined angle to improve feeding. It should also be clear that the structure of our invention allows the user to perform the task of forming the lips of a firearm magazine without additional tools in a field environment. Lastly, the anvil of the preferred embodiment can be utilized to detect and repair damage to the side walls of the magazine.