Abstract:
A projectile package loaded in a firearm includes a projectile having a rod attached to its rear region. The rod is attached to a drag member or vanes having elastic properties. When fired, the projectile is expelled from the barrel of the firearm. Upon exiting the barrel and until the projectile reaches its effective range, reactionary air forces caused by the projectile traveling through the air result in the elastic vanes orienting themselves in a tight formation behind the rear region of the projectile. As a result, the vanes do not detrimentally affect the aerodynamics of the projectile&#39;s flight within the effective range of the projectile. However, once the effective range of the projectile has been exceeded, the slower velocity of the projectile causes the elastic vanes to laterally fan or spread out so as to impede the forward progress of the projectile.

Description:
DEDICATORY CLAUSE 
     The invention described herein may be manufactured, used and licensed by or for the U.S. Government for U.S. Government purposes without payment of any royalties thereon. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention pertains to projectiles such as bullets, shotgun slugs and the like that are fired from a firearm. 
     2. Discussion of the Background 
     The maximum range of a projectile fired from a firearm is much greater than the effective range of the projectile. The effective range of a projectile is understood to be the range where the projectile&#39;s speed and accuracy are within its effective design parameters. As a fired projectile travels beyond a certain distance, the speed and accuracy of the projectile are diminished to levels below that for which the projectile was designed. 
     However, a projectile that travels past its effective range without hitting an intended target can still pose an extreme hazard to people and property located further down range. For example, a rifle bullet having an effective range of 300 yards may have an actual or maximum range of over two miles and can be extremely lethal after traveling for over a mile. 
     Thus, a weapon&#39;s maximum range must be considered before deciding to use the weapon in a given environment or setting. Big game hunting requires the use of weapons having high muzzle velocities. Yet, the maximum range of high-powered rifles creates a degree of danger even in rural settings. Mission success for police and military actions can require the use of high muzzle velocity weapons in densely populated urban areas where safety concerns become all the more obvious. 
     In some regions of the United States, no center-fire rifles are allowed for large game hunting and such hunting has been restricted to shotguns. Although shotgun slugs do not travel as far as a rifle bullet, shotgun-fired slugs are less accurate. Thus, even with decreased range, decreased accuracy is a cause for safety concerns. 
     SUMMARY OF THE INVENTION 
     The present invention allows a projectile fired from a firearm to achieve its full effective range while greatly reducing the projectile&#39;s maximum range. This reduction in the maximum range of the weapon greatly augments safety where the weapon is used. The present invention has particular applicability for hunting near populated areas and in military and police actions in urban settings. 
     In the present invention, a projectile fired from a firearm is allowed to perform as intended within its effective range with the forward progress of the projectile being severely impeded and retarded thereafter such that the maximum range of the projectile is severely reduced. This reduction in forward progress after traveling an effective-range distance is accomplished by attaching vanes or drag-creating members to the back of the projectile, with the vanes being designed to expand once the effective range of the projectile has been reached. 
     The present invention is a projectile package or projectile capsule which includes a projectile to be fired from a firearm, such as in a shotgun shell or bullet cartridge. 
     The projectile package includes a projectile having a front portion and a front tip. The body of the projectile is located between the front portion and a rear portion of the projectile. A rod is positioned to the rear of rear portion with a front end of the rod extending into the projectile and being securely connected thereto. The rod has a rear end positioned the furthest distance from the rear of rear portion of the projectile. The rod is aligned with a horizontal axis which extends through the center of the projectile and through the front tip of the projectile. The projectile is secured to a container, such as a shell case or casing. Vanes are connected to the rod. Propellant such as gunpowder is located within the container to the rear of the projectile. The container includes a primer. 
     When the projectile package is loaded in a firearm, once the primer is struck, the propellant is ignited causing the projectile to be expelled from the barrel of the firearm. Upon exiting the barrel and until the projectile reaches its effective range, the reactionary air forces caused by the projectile traveling through the air, cause the vanes to be positioned behind the rear of the projectile. Thus, the vanes do not detrimentally affect the aerodynamics of the projectile&#39;s flight within the effective range of the projectile. The vanes have elastic properties. Once the effective range of the projectile has been exceeded, the slower velocity of the projectile results in the vanes laterally spreading out so as to impede the forward progress of the projectile. 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
       A more complete appreciation of the invention and many of the attendant advantages thereof will be readily obtained by reference to the following detailed description when considered in connection with the accompanying drawings. 
         FIG. 1  is a perspective view of a safety projectile made in accordance with the present invention showing a rod extending from the rear portion of the projectile with the rod being aligned with a horizontal axis. 
         FIG. 2  is an exploded view demonstrating that the projectile and rod of the present invention can be connected by a screw-type assembly. 
         FIG. 3  is an exploded view demonstrating that the projectile and rod of the present invention can be connected by a press-fit assembly. 
         FIG. 4  is an x-ray-side view of a shell made in accordance with the present invention. 
         FIG. 5  is an x-ray-side view of a bullet cartridge made in accordance with the present invention. 
         FIG. 6  is a side view of a safety projectile of the present invention in flight just after having been fired from a gun but before exceeding the projectile&#39;s effective range. 
         FIG. 7  is a side view of a safety projectile of the present invention in flight after having exceeded its effective range but before coming to rest. 
         FIG. 8  is a side view of a safety projectile of the present invention which has finally come to rest after having been fired from a firearm. 
         FIG. 9  is a rear view of the fully extended vanes of the safety projectile of the present invention. 
         FIG. 10  is a graphical illustration comparing the distance traveled of a projectile equipped with vanes in accordance with the present invention and of a like projectile not so equipped. 
         FIG. 11  demonstrably portrays, in accordance with the present invention, how a missed shot fired from a hunter&#39;s rifle falls harmlessly to the ground before endangering a pedestrian in the line of fire. 
         FIG. 12  is a side view of a safety projectile of the present invention in flight just after having been fired from a gun but before exceeding the projectile&#39;s effective range, with the safety projectile employing a single elastic sail or drag member  33 . 
         FIG. 13  is a side view of a safety projectile of the present invention in flight after having exceeded its effective range but before coming to rest, with the single elastic sail or drag member fully deployed. 
     
    
    
     DETAILED DESCRIPTION 
     With reference to  FIG. 1 , a projectile  12  in accordance with the present invention has a front portion  14 , a rear portion  18  and a body  20 . The body  20  is located between the front portion  14  and rear portion  18  of projectile  12 . A front tip  16  is positioned at the forward most point of the front region  14 . A rod  24  has a front end  25  and a rear end  27 . The front end of rod  24  extends into the projectile  14  through a center hole  22  ( FIG. 2 ) located in the middle of rear portion  18 . The rear end  27  of rod  24  is positioned to the rear of rear portion  18 . Rod  24  is aligned on horizontal axis AA. Horizontal axis AA extends through rod  24  and through the front tip  16  of projectile  12 . Thus, horizontal axis AA extends horizontally through the center of projectile  12 . 
       FIG. 2  and  FIG. 3  demonstrate that rod  24  can be secured to projectile  12  by a screw-type connection or by press-fitting. Other methods can be used to create the rod  24  and projectile  12 , including form molding. 
     In reference to  FIG. 2 , rod  24  is provided with screw threads  28  for screwed connection with projectile  12 . In  FIG. 2 , projectile  12  is provided with grooves (not shown) for accommodating the screw threads  28 . Rod  24  is provided with a plurality of vanes  32 , which include vanes  32 A 1  and  32 A 2 . The vanes or drag-creating members  32  are positioned to the rear of projectile  12 . 
     In  FIG. 3 , rod  24  is provided with raised rings  30  for purposes of a press-fit connection with projectile  14 . When rod  24  is press-fit into center hole  22 , the raised rings  30  allow for a secure connection. 
     The projectile  12  can be made of lead or other metals or alloys and is not limited to a metal composition. Plastic projectiles or projectiles made from other structurally suitable compositions may be used. 
     In  FIG. 4 , projectile  12  is positioned within a housing or shell case  40 . Propellant or gun powder  38 A is provided within a metal head  48  (although the head  48  could be made of a material other than metal). Vanes  32  on rod  24  are positioned to the rear of projectile  12  in a vane accommodating region  42  of shell  40 . A primer  44 A is located at the center of the rim region  46 A. Rim region  46 A is attached to head  48 . In accordance with the present invention, the projectile  12 , rod  24 , vanes  32 , shell case  40 , propellant  38 A, and head  48  form a projectile package or shotgun shell  100 . 
     In  FIG. 5 , a projectile package or bullet cartridge  200  is provided with a projectile  12  connecting to rod  24  to which is secured vanes  32 . The vanes  32  are positioned to the rear of projectile  12  and are positioned within housing or case  50  in which the rear  18  of projectile  12  is securely attached or inserted. The vanes  32  are positioned within a portion  52  of casing  50  which is filled with gun powder or propellant  38 B. The propellant  38 B is connected to a primer  44 B centered at the rear of rim region  46 B. 
     With reference to  FIG. 6 , when a firearm utilizing a shell  100  ( FIG. 4 ) or bullet cartridge  200  ( FIG. 5 ) is fired, the projectile  12  exits the gun barrel and proceeds in a forward direction F. The reaction force R f  resulting from projectile  12  rapidly moving through the air causes vanes  32  to bend behind the rear  18  of projectile  12  so as not to impede the forward progress of the projectile  12 . Once the effective range of the projectile has been reached such that the speed of travel of the projectile is diminished, the reaction force R f  is diminished. 
     As the reaction force R f  is reduced, the elastic properties of vanes  32  causes the vanes to expand or fan out as shown in  FIG. 7 . The vanes  32  acts as a sail which drastically impedes the forward progress of the projectile  12  by creating drag. The vanes  32  cause projectile  12  to prematurely fall to the ground well before the maximum range of the projectile is achieved. 
     In a prototype of the present invention, the vanes  32  were constructed of a polymer (plastic) material, although other materials having appropriate elastic qualities could be used. The polymer or material selected for the vanes will depend on the velocity of the projectile and the projectile&#39;s effective maximum range. The material&#39;s modulus of elasticity will determine the restoring force required to expand the vanes and effect a termination of the projectile&#39;s flight. The modulus of elasticity can range from 350-3500 mega Pascal&#39;s (MPa). 
     The vanes can be made by injection molding and cutting of a ribbon or thin rod of the polymer to the required length. Injection molding of the rod and vanes in a simultaneous operation or mechanically attaching the vanes into holes or cutouts in the rod are two methods which can be used to affix the vanes to the rod, although the vanes can be attached to the rod by other methods. Attaching vanes by hole or cutouts is similar to a technique used to construct brooms and paint brushes. The elastic properties of the vanes are selected in accordance with muzzle speed, with the length of the vanes being necessarily limited due to packaging constraints. 
     In  FIG. 8 , the vanes  32  are fully extended and are not being met with wind resistance. Thus,  FIG. 8  is demonstrative of a fired projectile  12  which has come to rest. 
       FIG. 9  is a rear view of rod  24  with vanes  32  being in a fully extended, fanned-out position. 
     With reference to  FIG. 12 , the teachings of the present invention can be utilized in a single elastic sail or drag member  33  which is attached to rod  24  connecting to projectile  12 . The drag member  33  has an elasticity such that when the projectile is within its effective range, after having been fired from the firearm, reaction forces R f  cause the drag member  33  to assume a protected position behind the rear portion  18  of the projectile  12  so that the aerodynamic properties of the projectile are not detrimentally affected. After the projectile  12  has exceeded its effective range, and the reaction forces R f  are reduced as a result of a reduction in speed, the drag member  33  laterally spreads out so as to impede the forward progress of the projectile. 
     In  FIG. 10 , the graphical illustration shows a point A which is the starting point of a bullet&#39;s trajectory. The bullet reaches the end of its effective range at point B. If the bullet is of a type which utilizes the present invention, the bullet comes to rest at point C. If the bullet is not constructed in accordance with the present invention, the same caliber of bullet fired from the same weapon with the same amount of propellant will land at point D. 
     The practical effects of the present invention are demonstrated in  FIG. 11  where a hunter  70  is depicted firing his rifle  72  at a deer  80 . In that the aim of the hunter  70  was off, the resulting bullet path  75  misses the deer  80 . However, since the hunter was utilizing a bullet made in accordance with the teachings of the present invention, the bullet landed at point C just short of a field of wheat  90 . 
     What the hunter could not appreciate when he fired the gun was that a pedestrian  60  was walking nearly a mile away on the other side of the field of wheat  90 . If the hunter  70  had not been using a bullet in accordance with the present invention, the bullet which missed the deer could have struck the pedestrian  60 . 
     In a prototype of the present invention, a rigid central rod had plastic polymer string attached to it at various circumferential and axial locations. These strings were grouped and aligned to form vanes. This assembly was inserted into the base of a 12 gauge, 0.55 inch diameter slug. The rod extended the overall length of the slug by 70%. When fully extended, the vanes had a radius that was 70% greater than the radius of the slug. For the prototype, four sets of vanes were separated by 90 degrees. 
     However, it is understood that the invention may be practiced with any number of vanes or sets of vanes spaced apart at various distances and angles, and as demonstrated in the embodiment of  FIG. 12 , the vanes could be lumped together into a single circumferential mass so as to form a single sail or drag member. 
     As a proof of concept and verification of range reduction, both three-dimensional computational fluid dynamic (CFD) drag calculations and one-dimensional degree of freedom (1-DOF) flight predictions were made to examine the impact of the vane assembly on the flight path of the projectile. This research project examined the effects of the increased drag on the projectile, caused by the vanes as they extended into the flow field, at various speeds and locations along the flight path. 
     The results from the simulation indicated no significant effects on range/altitude/velocity within the effective 0 to 300 meter range. Downstream of the effective range the maximum range was reduced by up to 40%. What was further detected was that the vanes, like the vanes of an arrow, actually contributed to increasing the accuracy of the projectile within the projectile&#39;s effective range. 
     The simulation results and prototype demonstrated that while significantly reducing the actual range of a projectile, the present invention does not detrimentally affect the performance of the projectile within its effective range and actually enhances accuracy within the effective range. 
     The present invention has applicability to rifle and pistol bullets and to shotgun slugs; however, the invention is not limited to such originations or applications. 
     Accordingly, modifications are possible without deviating from the spirit of the present invention. Thus, the scope of the present invention is limited only by the claim language which follows hereafter.