Patent Publication Number: US-6209180-B1

Title: Non-toxic high density shot for shotshells

Description:
This application claims priority from provisional patent application Ser. No. 60/042,390, filed Mar. 25, 1997. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to a non-toxic high density shot for shotshells and to the method for making it. 
     2. Description of the Previously Published Art 
     It is desirable to manufacture non-toxic shot for shotshells that have a density at least as great as lead, as a replacement for lead in shotgun shells. 
     Currently, steel shot having a significantly lower density than lead is employed with less than satisfactory performance. 
     OBJECTS OF THE INVENTION 
     It is an object of this invention to provide a high density composite non-toxic shot for shotshells which has the same density as traditional Pb shotgun media. 
     It is further object of this invention to provide a process for making a high density composite non-toxic shot for shotshells which has the same or greater density as traditional Pb—Sn shotgun media. 
     It is a further object of this invention to provide a process for making non-toxic shot by coating a steel core particle with a higher density coating material so that the resultant composite product has about the same density as traditional Pb shotgun media. 
     These and further objects of the i invention will become apparent as the description of the invention proceeds. 
     SUMMARY OF THE INVENTION 
     The foregoing and further objects and advantages are obtained by coating a ferrous metal spherical core with a non-toxic coating material having a higher density than the density of the core material. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In the accompany drawings, 
     FIG. 1 is a cross-sectional view of a shot shell embodying the invention, and 
     FIG. 2 is a view like FIG. 1, showing an alternative form of the invention. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The current invention achieves the desired results by applying a high density coating to the surfaces of conventional steel shot at a sufficient thickness to approximate at least the density of lead in the coated composite articles. 
     As shown in FIGS. 1 and 2, in accordance with this invention, commercially available steel spheres having a density of 7.86 g/cm 3  may be coated with either tungsten having a density of 19.3 g/cm 3 , tungsten compounds such as ferro-tungsten having a density of 14.5 g/cm 3  or other high density, non-toxic materials. A coating of tungsten of 0.0061 inch thickness, for example, on a #6 steel shotgun pellet having a diameter of 0.110 inch would result in a bulk density of 11.3 g/cm 3 , which is equivalent to the density of pure lead (Pb). 
     FIG. 1 shows a spherical core  10  having a metallic coating layer  12 , while FIG. 2 shows a coating layer  12 ′ made from an epoxy-powder slurry. 
     The invention contemplates the possibility of coating steel spheres by a variety of processes including chemical vapor deposition (CVD), physical vapor deposition (PVD), electrolysis, plasma spraying, surface coating with composite slurries (e.g., epoxy and tungsten powder), surface coating by thermal bonding (e.g., sintering tungsten powder onto steel surfaces), and the like. 
     It is understood that the foregoing detailed description is given merely by way of illustration and that many variations may be made therein without departing from the spirit of this invention.