Abstract:
A tracer cylinder for use with a shotgun shell to provide an aiming and training aid for shotgun shooting sports, which also can be used for military and police applications. The tracer cylinder, which contains a liquid, has one or more openings, each one releasably closed with a valve. The tracer cylinder is loaded into a shotgun shell and fired. After the valve in the bottom of the cylinder is released, the liquid is extracted through the opening by physical forces, creating a long-lasting mist or fog cloud that is visible to the shooter. The shooter is provided with a consistent and durable reference, allowing him or her to make effective corrections to his or her shooting technique. The tracer cylinder can be loaded into a shot holder, with or without shot pellets.

Description:
FIELD OF INVENTION 
     This invention relates to shotgun ammunition, more specifically to tracers used to make the shot visible to shooters. This invention serves as a training aid to improve one&#39;s shooting ability for shotgun sports such as Trap, Skeet or Sporting Clays. It also serves as a shotgun aiming and training aid for hunters, with applications for military and police personnel. 
     BACKGROUND OF THE INVENTION 
     All shotgun sports require the shooter to accurately predict the trajectory of the target. Mastering the lead is the greatest challenge in shotgunning sports. The lead is defined as the distance in front of the moving target, which the shooter aims and shoots at in order to break the target. The particular lead will vary, depending on the application, shot type, shot speed, shooter&#39;s technique, speed and angle of the target, and atmospheric conditions; it can range from a few inches to more than ten feet. 
     The visibility of an object to the human eye generally depends on the size of the object, the relative distance between the object and the observer, the relative speed of the object, the color of the object, and the light intensity and atmospheric conditions. The human brain and eye refresh images approximately every 0.1 seconds, while the average shot flight time to the target ranges from approximately 0.05 to 0.3 seconds; this makes shooting moving objects a real challenge. 
     Inventors have developed tracers for shotgun shells in an attempt to aid the shooter in visualizing his or her shot with regard to the target. Prior inventions can be categorized as non-ignition and ignition type tracers. Each type has its limitations, including the risk of fire with pyrotechnic tracers and the complexity of manufacturing in the case of chemiluminescent tracers. Both types share a significant drawback: the fact that the shooter has a mere fraction of the second to see the tracer. This makes current inventions of limited value to shooters in providing a consistent and visible reference to aid them in correcting their shooting. 
     The prior art includes the following inventions:
     1. Shot-Shell (U.S. Pat. No. 1,304,962 to J. Gravely in 1919);   2. Shotgun Shell (U.S. Pat. No. 1,457,337 to E. Barrows in 1923);   3. Method and Apparatus for Forming Letters and Symbols in the Air (U.S. Pat. No. 1,716,794 to J. Remey, 1929);   4. Shotgun Cartridge (U.S. Pat. No. 1,887,990 to H. Brownsdon in 1932);   5. Artificial Production of Fog (U.S. Pat. No. 1,895,765 to U. Muller in 1933);   6. Method for Creating Aerial Effects (U.S. Pat. No. 2,062,511 to J. Haddock in 1936);   7. Tracer Shotshell (U.S. Pat. No. 3,262,390 to R. Cowles in 1966);   8. Apparatus for Producing Smoke or Fog (U.S. Pat. No. 3,244,641 to D. Durr in 1966);   9. Method and Means for Producing and Controlling the Discharge of Fog (U.S. Pat. No. 3,379,373 to R. Roberts in 1968);   10. Nebulizer (U.S. Pat. No. 3,652,015 to G. Beall in 1972);   11. Shotgun Shell Tracer Wad (U.S. Pat. No. 4,553,481 to V. Ricci in 1984);   12. Method and Apparatus for Sky Typing (U.S. Pat. No. 4,561,201 to G. Sanborn in 1985);   13. Efficient Artificial Smoke Generator (U.S. Pat. No. 4,836,452 to J. Fox in 1989);   14. Aerosol Diffusion Fogger (U.S. Pat. No. 5,057,243 to M. Becker in 1991);   15. Diffusion Fogger (U.S. Pat. No. 4,990,290 to J. Gill in 1991);   16. Tracer Cartridges (U.S. Pat. No. 5,429,054 to R. Topping in 1995);   17. Smoke Generator for Radio Controlled Aircraft (U.S. Pat. No. 5,932,978, to J. Geyer in 1999);   18. Compression Cartridge (U.S. Pat. No. 6,250,228 to F. King in 2003);   19. Shotgun Shell Flight Path Indicator (U.S. Pat. No. 6,539,873 to E. W. Diller in 2003);   20. Ballistic Tracer Platform for Shotgun Ammunition (U.S. Pat. No. 10,656,471 to J. Dunnam and M. Quintana in 2007).   

     An improved design would overcome the drawbacks of the prior art and would fulfill the following criteria:
         (a) Provide the shooter with a consistent and accurate reference to the target.   (b) Give the shooter more time to see the tracer with reference to the target; in other words the improved design should have memory.   (c) Be safe to use and environmentally friendly.   (d) Be simple and economical to manufacture.   (e) Be entertaining to the shooter.       

     SUMMARY OF INVENTION 
     The present invention provides an innovative design for a tracer that comprises a tracer cylinder that contains a liquid, which utilizes appropriate valves, and which, when loaded into a shotgun shell and fired, has the means to release the liquid and emit a thick and long-lasting mist or fog cloud that provides the shooter with a consistent and durable reference, allowing him or her to make effective corrections to his or her shooting technique. The invention uses any one of a variety of liquid compounds, such as vegetable oil, mineral oil, synthetic oil, paints, water, aqueous gels, and known fogging liquids such as titanium tetrachloride (TiCl 4 ). When water or an aqueous gel is used, various dyes, pigments, and/or reflective particles are added in order to make the fog cloud more visible to the shooter. This invention can be modified and can be used with all shot types and in many shotgun gauges, including 8, 10, 12, 16, 20, 28 and 410. 
     In accordance with the present invention, the tracer comprises a cylinder with a length equal to or larger than its diameter, thereby ensuring its accuracy. Holding the liquid of choice, the cylinder is loaded into a typical shotgun shell, strategically located in front of the shot pellets in order to minimize the structural stresses on the cylinder resulting from ignition of the propellant. The cylinder is typically separated and protected from the shot by a disc-type spacer. Alternatively, it can be loaded into the shot holder of a wad, with no shot pellets. In either case, the shot cup petals protect it during firing and acceleration of the wad and cylinder down the barrel. The cylinder can be sized to have different internal and exterior diameters and length combinations in order to adjust the volume of liquid, depending on the shotgun gauge with which it is used and other variables, such as the distance to the target and the size and type of shot. 
     The tracer cylinder has a disk-shaped top cap and a bottom portion defining a cavity; the two parts are glued or welded together before the liquid is injected into the cavity. The cylinder has at least two small openings that are strategically located, one in the center of the top cap and another in the bottom side of the cylinder, also in the center. The openings allow the liquid to be extracted from the cylinder due to the difference in pressure between the liquid inside the cylinder and the low pressure air surrounding the sides and bottom portion of the cylinder created as the cylinder moves rapidly through the air. Upon exiting the cylinder through the bottom opening, the miniature droplets of liquid create a mist or fog cloud, which is contained by the cone of air created at the rear of the cylinder, thereby increasing its density and making it visible for several seconds. This lasting fog cloud is visible to the eye in much the same way as a contrail or the tail of a comet, and it is easily seen by the shooter. 
     Each of the openings in the cylinder is fitted with a valve in order to prevent the liquid from exiting the cylinder before ignition of the shotgun shell. Upon firing, each valve is displaced, either by inertial forces present during the cylinder&#39;s acceleration in the barrel or by drag forces once the cylinder is airborne, without affecting the accurate movement of the cylinder in front of the shot. 
     Alternatively, the cylinder can also be fitted with symmetrically-positioned openings on its sidewall, each one using a drag-type valve. The addition of such openings allow the manufacturer to adjust the amount of liquid being expelled from the cylinder, affecting the diameter, density and duration of the fog cloud created. 
     It is an object of the present invention to provide a tracer comprising a cylinder that contains a liquid which, after exiting the barrel of a shotgun, produces a mist or fog cloud that accurately traces the shot and is easily visible to the shooter for a sufficient amount of time so that it can be effectively used to help him or her with his or her shooting technique. 
     Another object of this invention is to provide the means by which the liquid contained in the cylinder can be released without negatively affecting the accuracy of the tracer. 
     Still another object of this invention is to provide a tracer comprising a cylinder filled with liquid which, after exiting the barrel, produces a fog cloud similar to that of a comet trail or contrail, the invention providing the means to adjust the diameter and length of the cylinder, as well as the density and duration of the tracing effect, depending on the gauge of the shotgun shell and the application with which it is to be used. 
     A further object of this invention is to provide a tracer for shotgun ammunition, the device being accurate and safe to use in single barrel, double barrel and semi-automatic shotguns, and, further, being structurally sound and able to withstand the high stresses associated with its application. 
     Further objects and advantages of this invention will become apparent from a consideration of the drawings and description, infra. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an isometric view of a shotgun shell containing the tracer cylinder of the present invention. 
         FIG. 2  is a sectional side view of the shell of  FIG. 1 , taken along line  2 - 2 , showing the tracer cylinder strategically positioned in the shotgun shell, in front of the shot. 
         FIG. 3  is an isometric view of an alternative shotgun shell containing the tracer cylinder of the present invention. 
         FIG. 4  is a sectional side view of the alternative shotgun shell containing the tracer cylinder illustrated in  FIG. 3  taken along line  4 - 4 . 
         FIG. 5  is an enlarged cross-sectional view of the top of the alternative shotgun shell containing the tracer cylinder illustrated in  FIG. 4  taken along line  5 - 5 . 
         FIG. 6  is an enlarged cross-sectional view of wad inside of the alternative shotgun shell containing the tracer cylinder illustrated in  FIG. 4  taken along line  6 - 6 . 
         FIG. 7  is a sectional side view of an empty tracer cylinder, without valves. 
         FIG. 8  is a sectional side view of a tracer cylinder containing liquid, with a cone-shaped valve pressed against the small opening in the top cap and a disk-shaped valve with an interference fit into the opening on the bottom portion of the cylinder in order to keep the liquid inside the cylinder. 
         FIG. 9  shows a sectional side view of an airborne tracer cylinder after the shell has been fired from a shotgun, the cone-shaped valve having been displaced as a result of inertial forces, and the disk-shaped valve having fallen away due to air drag forces, the liquid being released into the atmosphere by the vacuum created in the air surrounding the tracer cylinder. 
         FIG. 10  is a sectional side view showing optional lateral openings, one with a valve, in the sidewall of the tracer cylinder. 
         FIG. 11  is a top view of an alternate two-part valve that can be used to seal the opening in the cap of the tracer cylinder. 
         FIG. 12  is a sectional view of the alternate two-part valve shown in  FIG. 11 , taken along line  12 - 12 . 
         FIG. 13  is a sectional view of the cylinder shown in  FIG. 11 , showing the alternate valve after the cylinder leaves the barrel and how it is displaced by air drag forces. 
         FIGS. 14A through 14D  are sequential sectional side views of the tracer cylinder before and after ignition of the shell, showing the displacement of the valves and the release of the liquid from the tracer cylinder. 
         FIG. 15  is a representational view of a shooter using the tracer cylinder of the present invention while shooting at a clay target. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The present invention is designed to be used in a typical shotgun shell  1 , which generally has a hull  2  with a metal base cap  3  and a crimped top  4 , as shown in  FIG. 1 . 
     The sectional view in  FIG. 2  shows the shotgun shell  1  with hull  2  and base cap  3 , which has been assembled to hold the tracer cylinder  5  containing the tracer liquid  6 , which is positioned in front of or on top of the shot pellets  7 , separated therefrom and protected by a disk-shaped spacer  8 , made of plastic, felt, cardboard, cork, or a similar commonly-used material. The shot pellets  7  are enclosed in a shot cup  9 , which incorporates a gas seal  10  that is in direct contact with the propellant  11 , which is next to the primer  12  at the lower end of the shotgun shell  1 . The cylinder  5  consists of a top cap  13  with a radial indentation  14  and a container  15 . The radial indentation  14 , or step, provides more contact surface for glueing or welding the cap  13  to the container  15 . It also permits easier and more accurate alignment of the two parts. The cap  13  has an opening  16  that has been sealed with a press-fit inertial valve  17 . The bottom of the container  15  has an opening  18  that has been sealed with a drag-type, disk-shaped valve  19 . Together the valves  17 ,  19  keep the tracer liquid  6  from spilling out of the tracer cylinder  5  prior to use. The tracer liquid  6  used can be any one of a variety of liquid compounds, such as vegetable oil, mineral oil, synthetic oil, paint, water, and aqueous gels, as well as known fogging liquids such as titanium tetrachloride (TiCl 4 ). When water or an aqueous gel is used, various dyes, pigments, and/or reflective particles are added in order to make the fog cloud more visible to the shooter. The space between the cylindrical sidewall  20  of the container  15  and the shot cup  9  is typically filled, either by using a shot cup  9  with petals having thickened upper portions, or by inserting a resilient spacer. 
     Shown in  FIG. 3  is an alternative shotgun shell  21 , which generally has a hull  2  with a metal base cap  3  and a crimped top  4 . 
     As shown in  FIG. 4 , when used with the alternative shotgun shell  21 , the tracer cylinder  5 , with container  15  holding tracer liquid  6 , can be loaded into a conventional wad without any shot pellets, particularly when a shooter wishes to fire it merely as an indicator or reference. When this embodiment is assembled, a cylindrical wad  22 , made from polypropylene, polyethylene, or another high-strength plastic, is placed inside the hull  2  of the shell  21  above the propellant  11  inside base cap  2 . The wad  22  is typically formed with shock-absorbing compression columns  23   a ,  23   b , ( 23   c ,  23   d ) and has a gas seal  24  formed in its lower end. The tracer cylinder  5  is then placed into the wad shot holder  25 , inside the petals  26   a ,  26   b , ( 26   c ,  26   d ), which surround the sidewall  20  and cushion the tracer cylinder  5  during ignition, and which open and fall away when the tracer cylinder  5  is in flight. Like the tracer cylinder  5  in  FIG. 2 , the container  15  has an upper opening  16  that has been sealed with a press-fit inertial valve  17 , and a lower opening  18  that has been sealed with a drag-type, disk-shaped valve  19 . 
       FIG. 5  shows the sidewall  20  of the container  15  inside the petals  26   a ,  26   b ,  26   c ,  26   d  of the shot holder  25  inside the hull  2 . The opening  18  has been sealed with a protrusion  31  on the top of disk-shaped valve  19 , and the container  15  has been filled with tracer liquid  6 . 
       FIG. 6  shows the shock-absorbing compression columns  23   a ,  23   b ,  23   c ,  23   d  of the wad  22  inside the hull  2 , as well as the gas seal  24 . 
       FIG. 7  shows an empty tracer cylinder  5 , consisting of a disk-shaped top cap  13  with radial indentation  14  and a cylindrical container  15 , which are glued or welded together, creating a cavity  30 . Both parts of the cylinder  5  are typically made from a high-strength plastic, such as polypropylene or polyethylene, or from nylon, using standard high volume processes, including injection molding and high-speed screw machines. Alternatively, the top cap  13  and container  15  can be made from a metal, such as brass, aluminum, copper or steel, using stamping and deep drawing techniques. Optimally, the top cap  13  can be formed to have a small, centrally-located opening  16 ; the container  15  has a small, centrally-located opening  18  in its bottom side. The size of each opening can range from approximately 0.5% to 5% of the diameter of the cylinder  5 , depending on the number of openings used, the speed at which the cylinder will travel, and the type and viscosity of the liquid used as a tracer. The openings need to be small enough to extract minute droplets of liquid in order to create a mist or fog cloud upon exiting the cylinder, yet large enough to allow the liquid to flow out of the cylinder due to the difference in pressure exerted on the liquid inside the cylinder and the low pressure air surrounding the sides and bottom portion of the cylinder. The top cap  13  and the container  15  are joined together before the tracer liquid  6  is injected into the cavity  30 . The joining process can be performed in a number of ways, such as using a combination of specialized high strength glues and accelerators, soldering, or welding, including ultrasonic welding. 
       FIG. 8  is a sectional view of the cylinder  5  shown in  FIG. 7 , which has been filled with tracer liquid  6  and is shown with two openings, each sealed with a valve in order to keep the tracer liquid  6  from leaking from the cylinder  5  before ignition. The first is a cone-shaped inertial valve  17  pressed into the small opening  16  in the top cap  13 , and the second is a drag-type, disk-shaped valve  19  with a centrally-located protrusion  31  that interference-fits into the opening  18  in the bottom of the container  15 . The tracer cylinder  5  can perform effectively with only the opening  18  releasably sealed with the disk-shaped valve  19 . In any event, the number of valves used will depend on the number and location of the openings. 
     The inertial cone-shaped valve  17 , which can be made from metal or plastic, must be press-fit into the opening  16  from the lower side of the top cap  13  and before the top cap  13  and container  15  of the cylinder  5  are glued or welded together. The cylinder  5  is then flipped over, and the tracer liquid  6  is injected into the cavity  30  through opening  18 . The tracer liquid  6  is loaded into the cylinder  5  at atmospheric pressure or at a slightly higher pressure to aid in the flow of the tracer liquid  6  out of the tracer cylinder  5 , depending on the type of shell  1  used and the distance to the target. Opening  18  is then releasably sealed, using a disk-shaped valve  19 , which generally has a diameter that is slightly larger than the diameter of the cylinder  5  so that its edges extend past the sidewall  20  of the container  15 . The disk-shaped valve  19  can be made from plastic, rubber, or metal, using standard injection molding and stamping processes. The disk-shaped valve  19  has a cone-shaped protrusion  31  in its center that is interference-fitted into the opening  18  in the bottom of the container  15 . 
       FIG. 9  shows a sectional view of the tracer cylinder  5  of  FIG. 8  once it is airborne and after the shotgun shell ( 1  or  21 ) has been fired. The cone-shaped inertial valve  17  is shown resting on the bottom of the container  15 , having been displaced from the opening  16  in the top cap  13  by inertial forces during acceleration. The disk-shaped valve  19  has been detached due to air drag forces exerted on its edges after the tracer cylinder  5  is airborne. Because of the symmetrical arrangement of the valves, their removal occurs without affecting the accuracy of the cylinder  5 . In accordance with the physical law of conservation of energy and mass, after the valves  17 ,  19  are removed, the tracer liquid  6  in the tracer cylinder  5  is drawn out through the bottom opening  18  due to the low-pressure area surrounding the cylinder  5  upon flight. 
     The small opening  16  in the top cap  13 , while not necessary for the expulsion of the tracer liquid  6 , helps to avoid the collapse of the cylinder&#39;s  5  structure which may otherwise result from the vacuum created when the tracer liquid  6  leaves the cylinder  5  thereby assuring the reliability and effectiveness of the device. Further, the opening  16  helps balance the pressure within the cylinder  5 , thereby facilitating the extraction of the tracer liquid  6 . When the cylinder  5  is constructed with opening  16 , the inertial valve  17  is displaced when the shell  1  is ignited, after which it falls through the tracer liquid  6 , which slows its movement, before it settles on the bottom of the container  15 , without blocking the bottom opening  18 . Once the cylinder  5  is airborne, air drag forces on the edges of the disk-shaped valve  19  cause it to become detached from the bottom of the container  15 , allowing the tracer liquid  6  to be drawn from the cylinder  5  into the atmosphere. Because the disk-shaped valve  19  is symmetrically positioned on the bottom side of the container  15 , it separates without affecting the accuracy of the device. The tracer liquid  6  exits through the small opening  18  in the form of small droplets  32 , which create a fog mist or cloud that is highly visible to the shooter (i.e., the sunlight reflects off the increased surface area of the droplets). Because only small droplets  32  are released from the cylinder  5 , the amount of tracer liquid  6  the cylinder  5  must hold can be very small and, therefore, the device is extremely efficient. Because the tracer liquid  6  exits the cylinder  5  through the bottom opening, the fog cloud created is contained within the cone of air created by the air stream at the back of the cylinder  5 , thereby increasing its density and making it visible for several seconds. This long-lasting fog cloud mimics the tail of a comet and is easily seen by the shooter. 
       FIG. 10  is a sectional view of an alternate embodiment of the cylinder  5 , showing symmetrically-positioned lateral openings  35 ,  36  in the sidewall  20  of container  15 , which can be used to increase the flow and visual effects of the tracer liquid  6  when it enters the atmosphere. Each opening  35 ,  36  is or will be sealed with a drag-type sidewall valve  38 , which has been press-fit into place. Each sidewall valve  38  can be made from plastic, rubber or metal, and is formed with disc-shaped or rectangular parts that are slightly curved to match the outer surface of the container  15 . Each sidewall valve  38  has a centrally-positioned, cone-shaped protrusion  39 , which is inserted into an opening  35 ,  36  in order to seal it. Once the cylinder  5  is airborne, air drag forces on the cylinder  5  remove sidewall valve  38  and allow the tracer liquid  6  to be extracted from the cavity  30 . Again, because of the symmetrical positions of the openings and valves, the accuracy of the device is not negatively affected when the sidewall valve  38  and the disk-shaped valve  19  are released. The addition of lateral openings  35 ,  36  can be used to increase the diameter, density and duration of the fog cloud created. For instance, the amount of tracer liquid  6  being expelled can be adjusted in order to produce a fog cloud that mimics the shot pattern. This embodiment is particularly effective when the target is engaged at short distances. Because the tracer liquid  6  is extracted from the cylinder  5  more rapidly, the fog cloud created has a larger diameter, thereby helping the shooter better visualize his or her shot. 
       FIG. 11  is a top view of another type of valve that can be used to seal the opening in the top cap  13 . The two-part valve  40  consists of two complementary sections: a first section  41  and a second section  45 . The first section  41  has a bar  42  having an opening  43  formed in one end and an annular portion  44  attached to the other end. The second section  45  has a bar  46  having a protrusion  47  on the first end and an annular portion  48  attached to the other end. Both sections  41 ,  45  can be made from plastic or metal, using standard manufacturing processes, such as metal stamping or injection-molding. The first section  41  and the second section  45  are aligned and the protrusion  47  of the second section  45  is inserted through the opening  43  of the first section  41 , then into the opening  16  in the top cap  13 . When the valve  40  is installed, the annular portions  44 ,  48  extend past the outer circumference of the top cap  13 . 
       FIG. 12  is a sectional view of the two-part valve  40  of  FIG. 11  showing how the first section  41  and the second section  45  interlock and close the opening  16  in the top cap  13 . The protrusion  47  of the second section  45  has been inserted through the opening  43  of the first section  41 , then press-fit into opening  16  of the top cap  13 . Annular portions  44 ,  48  extend past the outer circumference of the top cap  13 . It is important to note that, in order for valve  40  to work properly, the total projected area of the annular sections  44 ,  48  needs to be larger than the total projected area of the bars  42 ,  46 . 
       FIG. 13  is a sectional view of the tracer cylinder  5  shown in  FIG. 10 , which has the disk-shaped valve  19  shown in  FIG. 8  and the two-part valve  40  shown in  FIG. 11 . Both of the valves  19 ,  40  have been detached after the cylinder  5  is airborne. Air drag forces on the edges of the disk-shaped valve  19  cause it to separate from the tracer cylinder  5  and unplug the opening  18  in the bottom of container  15 . The same forces exerted on the annular portions  44 ,  48  of the two-part valve  40  impart a movement, causing the first section  41  and the second section  45  to rotate in opposite directions, one clockwise and the other counter-clockwise, causing them to separate and fall away from the top cap  13 , exposing the opening  16  to the air. 
     In still another embodiment, the cylinder can be enclosed in an annular cylinder made of plastic, cardboard or paper, to accommodate the use and production of a standardized tracer device that can be used in different shotgun gauges. 
       FIGS. 14A-14D  show the typical movement of the tracer cylinder  5  before and after ignition of the shotgun shell  1 . 
     In  FIG. 14A , the shotgun shell  1 , containing a shot cup  9  with shot pellets  7 , has been loaded into the shotgun barrel  50 , along with the cylinder  5  holding tracer liquid  6 . The primer  12  ignites the propellant  11 , and gasses expand into the gas seal cavity  10 . 
     In  FIG. 14B , the expanding gases  51  of ignition propel the shot cup  9  with shot pellets  7  and the cylinder  5  holding the tracer liquid  6  through the shotgun barrel  50 . The forces of ignition have displaced the inertial valve  17  from the opening  16  in the top cap  13 . 
     In  FIG. 14C , after leaving the shotgun barrel  50 , the shot cup  9  has flipped out of the way of the scattering shot pellets  7 . The spacer  8  has also flipped out of the way, the disk-shaped valve  19  has been detached, and the cylinder  5  continues to travel in front of the pattern of shot pellets  7 . 
     As shown in  FIG. 14D , the tracer liquid  6  is being drawn from the opening  18  in the bottom of the cylinder  5 , creating a fog cloud  52 , which coincides with the pattern of shot pellets  7 . 
       FIG. 15  shows a shooter  55  using the tracer cylinder  5  of the present invention. The shooter  55  has loaded his shotgun barrel  50  with the shotgun shell ( 1  or  21 ), as he would load any other ammunition. The shooter  55  has aimed at the clay target  60  and has fired. The cylinder  5  has left the shotgun barrel  50 , in front of the shot string  56   a ,  56   b ,  56   c ,  56   d , leaving a fog cloud  52  streaming through the center of the expanding pattern of shot pellets in the shot string  56 . The shot cup  9  and spacer  8  have flipped out of the way. If the shooter  55  hits the clay target  60 , it breaks into pieces  61 . If he misses the clay target  60 , the shooter  55  would correct his lead or aiming point, according to the relative position of the fog cloud to the clay target  60 . 
     The information in the disclosure and description of the invention itself are illustrative only of the application of the principles of the present invention. Modifications and alternative embodiments may be devised by those skilled in the art without departing from the spirit and scope of the present invention.