Abstract:
A projectile is provided for delivering a payload from a smoothbore launcher to a target. The projectile includes an aerodynamic stabilizer, an extender along which the stabilizer can longitudinally translate, and a chamber connected to the extender to contain the payload. The chamber can include a plastic bag for containing a liquid that represents the payload, and a plurality of holes that radially extend through its wall. The stabilizer enhances post-launch directional stability of the projectile by longitudinally translating rearward along the extender to shift center of pressure of the projectile aft of center of gravity of the projectile. The bag ruptures upon contact with the target, thereby disbursing the liquid through the holes. The bag can include malodorant or paint. The projectile can be contained within a gunpowder-loaded shotgun shell for launch.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
   Pursuant to 35 U.S.C. §119, the benefit of priority from provisional application 60/877,016, with a filing date of Dec. 7, 2007, is claimed for this non-provisional application. 

   STATEMENT OF GOVERNMENT INTEREST 
   The invention described was made in the performance of official duties by one or more employees of the Department of the Navy, and thus, the invention herein may be manufactured, used or licensed by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor. 

   BACKGROUND 
   The invention relates generally to non-lethal smoothbore projectiles. In particular, this invention provides components and assembly of smoothbore projectiles for enhanced delivery of non-lethal liquid substances to be dispersed (or alternatively a solid round) with improved accuracy and increased range. 
   Uniformed civil authorities (e.g., law enforcement officials) can be tasked with mob dispersal, such as by riot control procedures and equipment, including release of chemicals that produce sensory irritation and/or temporary physical disablement, known as riot control agents. United States military personnel are prohibited by the Chemical Weapons Convention (ratified April 1997) from “method of warfare” use of such agents that include Oleoresin Capsicum (OC) and Lachrymator. As a consequence of prohibition on “method of war” usage, the United States Armed Forces do not employ RCA substances as anti-personnel weapons, whether for crowd control, interdiction, arrest or other law enforcement uses. 
   OC, popularly called “pepper spray”, is biodegradable and can be obtained from cayenne&#39;s oily resin. Contact with OC particles induces irritation in skin, eyes, respiratory tract and mucus membranes, rendered inert by proper ventilation and water flushing of the affected tissues. Carriers for OC aerosol delivery to spray against a target have included water, isopropyl-alcohol, methylene chloride, etc. Lachrymator can be used as tear gas that stimulates the corneal nerves in the eyes to induce tears, pain and even temporary blindness. Commonly used chemicals used as lachrymators include bromoacetone, benzylchloride, thiophene, xylyl bromide, chlorine and bromine. 
   The burning and painful sensations associated with capsaicin result from its chemical interaction with sensory neurons. Capsaicin, as a member of the vanilloid family, binds to an ion channel-type receptor that permits cations to pass through a cell membrane. In response, the neuron depolarizes, stimulating a signal to the brain, thereby producing the same sensation that excessive heat or abrasive damage would cause. At standard conditions (room temperature and pressure), capsaicin is a solid. Hence aerosol delivery of capsaicin may involve nebulization of a capsaicin-saline solution that includes diethyleneglycolmonoethylether (DGME) and ethanol as an aerosol vehicle. 
   SUMMARY 
   Conventional delivery mechanisms of liquid splash rounds yield disadvantages addressed by various exemplary embodiments of the present invention. In particular, the embodiments described below provide larger payload carrying capacity coupled with improved accuracy at greater ranges than available with conventional means. 
   Various exemplary embodiments provide a non-penetrating splash round containing a liquid payload that is non-lethal and accurate at ranges commensurate with current rules of engagement in narcotics interdiction and law enforcement. The delivery system contains the liquid integrally during storage and during delivery to the target, where upon impact the liquid dispenses (by disbursement). The splash round may be dispatched by a smoothbore launcher, such as a 12-gauge shotgun. 
   Various exemplary embodiments provide a projectile for delivering a payload from a smoothbore launcher to a target. The projectile includes an aerodynamic stabilizer, an extender along which the stabilizer can longitudinally translate, and a chamber connected to the extender to contain the payload. 
   In various exemplary embodiments, the chamber includes a plastic bag for containing a liquid that represents the payload, and a plurality of holes that radially extend through its wall. The stabilizer enhances post-launch directional stability of the projectile by longitudinally translating rearward along the extender to shift center of pressure of the projectile aft of center of gravity of the projectile. The bag ruptures upon contact with the target, thereby disbursing the liquid through the holes. The bag can include malodorant, paint or other desired liquid. The projectile can be contained within a gunpowder-loaded shotgun shell for launch. In alternate embodiments, the payload in the chamber can be solid rubber. 
   Various exemplary embodiments also provide a mount to rigidly attach the extender chamber to the extender, for which the stabilizer slidably translates along said extender, along with a governor to limit longitudinal translation of the stabilizer along the extender. The stabilizer can include a ring that slidably connects to said extender and a plurality of fins attached to said ring. The chamber can further include a weighted nose cap to shift the projectile&#39;s center of gravity forward. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     These and various other features and aspects of various exemplary embodiments will be readily understood with reference to the following detailed description taken in conjunction with the accompanying drawings, in which like or similar numbers are used throughout, and in which: 
       FIGS. 1A-1C  are perspective view of smoothbore projectile assemblies and their components; 
       FIG. 2  is an elevation view of smoothbore projectile components; 
       FIGS. 3A and 3B  are perspective views of smoothbore projectiles; and 
       FIG. 4  is a perspective view of a projectile adjacent a shotgun shell. 
   

   DETAILED DESCRIPTION 
   In the following detailed description of exemplary embodiments of the invention, reference is made to the accompanying drawings that form a part hereof, and in which is shown by way of illustration specific exemplary embodiments in which the invention may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention. Other embodiments may be utilized, and logical, mechanical, and other changes may be made without departing from the spirit or scope of the present invention. The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the present invention is defined only by the appended claims. 
   Smoothbore Projectile: Delivery of a riot control agent (RCA) to a target can be accomplished by launching a projectile that contains the RCA towards the target. The projectile is intended for propelled ejection from a medium-to-large-caliber smoothbore barrel, such as a shotgun or grenade launcher. For example, a violent or threatening person(s) can be targeted by a projectile as described for various exemplary embodiments. 
   In various exemplary embodiments for a common shotgun, the projectile contains a liquid or solid non-lethal payload of five milliliters (5 ml) for delivery as a “splash-round” to a target to a distance range of 80-100 yards in an accurate and repeatable fashion for improved reliability. By contrast, conventional paintball delivery systems deliver a payload accurately only to 20 or 30 yards with the payload of only one-to-two milliliters (1-2 ml). Thus, the exemplary delivery system for common shotgun weapons delivers a factor of two-to-four more payload accurately out to three-to-five times greater distances. The smoothbore delivery system can also be utilized in any size shotgun bore, e.g., 37 mm flaregun, 40 mm grenade, or any other smoothbore weapons. 
     FIG. 1A  shows a perspective view of exemplary embodiments for a smoothbore projectile, including component and assembly items  100 . A plastic cup  110  as a cylindrical tube having an open fore nose  115  and an aft closure  120  forms the payload-containing shell of the projectile. The cup  110  is designed to contain a sealed plastic bag inserted through the nose  115 . The cup  110  represents a containment chamber for the payload. The cup  110  may be longitudinally cylindrical in preferred embodiments, but artisans of ordinary skill will recognize alternate shapes to accomplish these objectives. 
   The bag may be filled with a clear liquid, such as shown in a clear polymer bag  130 , or alternatively a paint suspension, such as shown in an opaque polymer bag  135 . The cup  110  containing the opaque bag  135  is shown as a filled shell body  140 . The cup  110  may include small through-holes through its cylindrical wall, as well as an orifice (see  FIG. 2 ) at the aft closure  120 , for reasons discussed subsequently. The bag  130 ,  135  may be composed of fluorinated ethylene propylene (FEP) resin called Teflon® FEP from DuPont, with a thickness of 0.004 inch (4 mil) and a volumetric capacity of five milliliters. Upon impact with the target, the sudden deceleration causes the bag to rupture, releasing the liquid contained therein to be ejected through the through-holes. 
   The projectile can be directionally stabilized by a multi-fin tail  150  that optionally may include a thin disk  145  ( FIG. 1C ) at its fore. The tail  150 , which can be molded from urethane, includes an attach ring  155 , a distal portion (or gap)  160  and a set of four rectangular fins  165  in cruciform pattern extending from the attach ring  155 . The fins  165  are typically straight for fin stabilization, but alternatively may optionally be twisted along an axial direction of the projectile to provide spin stabilization. Other geometries for fin arrangement, cross-section and planform may be used to represent a comparable aerodynamic stabilizer without departing from the scope of the claims. 
   A rear-facing shaft  170  extends longitudinally from the aft closure  120  of the cup  110  along the projectile&#39;s axis of symmetry, and may be attached via the orifice therethrough. Connection of the shaft  170  to the closure  120  is described further herein, and various attachment techniques can be considered without departing from the scope of the invention. 
   The ring  155  can slide along the shaft  170 . During storage and loading, the ring  155  may abut against the aft closure  120  to reduce occupation volume and improve handling structural integrity. After launch of the projectile, aerodynamic drag against the fins  165  pushes the tail  150  rearward along the shaft  170 . An optional helical spring  175  may provide supplemental force to translate the tail  150  rearward along the shaft  170 . Further, alternate tail extension devices besides a shaft may be envisioned by artisans of ordinary skill, including an integral tail-extension device that longitudinally translates towards or away from the cup  110 . 
   The fore end of the cup  110  can be sealed with a weighted cap  180 . The fins  165  provide lateral aerodynamic stability for the projectile and rearward translation along the shaft  170  shifts the projectile&#39;s center of pressure to be aft of the center of gravity (or of gravity) that can be designed towards the nose  115  by the cap  180 . 
   These components can be combined together as a delivery assembly  190 . A scale comparison to a ruler  195  illustrates generalized size of the projectile and its components  100  for a shotgun-sized projectile. Alternatively, the cup  110  and the shaft  170  may be injection molded together in a single piece out of hard polymer.  FIG. 1B  shows a perspective view of the exploded components of the projectile, including the cap  180  and spring  175  as respectively separate from the cup  110  and shaft  175 .  FIG. 1C  shows a perspective of the assembly  190 , together with the disk  145  as labeled. 
   The cap  180  may be composed, for example of epoxy cement loaded with tungsten powder to plug the nose  115  of the cup  110 . The cap  180  of a 12-gauge shell may contain, for example, five grams (5 g) tungsten powder with two grams (2 g) epoxy. By weighting the cap  180  and extending the tail  150 , the projectile&#39;s center of gravity may be positioned forward of the center of pressure, thereby fin-stabilizing the projectile in flight. Alternate compositions for weighting the forward tip of the projectile may also be considered without departing from the invention&#39;s scope. 
     FIG. 2  shows an elevation view of a smoothbore 12-gauge projectile  200  in partially exploded form. The plastic cup  110  contains the sealed plastic bag  130  (or  135 ) filled with clear or opaque liquid and sealed at the nose  115  by the weighted cap  180 . A threaded orifice  210  for mounting the tail  150  penetrates the cup&#39;s aft closure  120  and is aligned with the axi-symmetric centerline of the cup  110 . To produce the orifice  210 , the cup  110 , preferably composed of a commercial polymer, may be tapped with a 10-32 thread. 
   The cup  110  may include through-holes  220  that penetrate through its cylindrical wall. Exemplary dimensions of the cup  110  for launch from a 12-gauge shotgun shell may include exterior cylinder wall diameter of 0.725 inch, an exterior length of 1.625 inch, and an interior diameter of 0.650 inch. The closure  120  may have a thickness of 0.375 inch, with an extension rim of 0.125 inch to the cup&#39;s end as a spacer to the tail  150 . 
   The tail  150  includes the proximal ring  155  having a through-hole  230 , the aft distal gap  160  and the cruciform fins  165  mounted to the ring  155 . The tail  150  may preferably be composed of polyurethane and/or a light metal, and the ring  155  and fins  165  may be composed of a unitary item. The tail&#39;s through-hole  230  aligns coaxially with the threaded orifice  210  in the cup  110 . Exemplary dimensions of the tail  150  for launch from a 12-gauge shotgun shell may include radial extension of the fin to 0.750 inch and a length of 0.750 inch. 
   The shaft  170  may be mounted to a threaded plug  240  at its proximal end and terminates with a knob  250  at its distal end for inhibiting the ring  155  from detaching from the shaft  170 . Thus, the plug  240  represents a rigid mounting mechanism, whereas the knob  250  represents a governor to limit the tail&#39;s axial motion. The shaft  170  and/or plug  240  may be preferably composed of a light metal, such as titanium and aluminum, or alternatively a strong light plastic. A thin disk  145  ( FIG. 1C ) may optionally be attached to the fins&#39; fore end with a foam spacer to confine the gunpowder and thereby improve combustion. The spring  175  may be disposed between the plug  240  and the knob  250  to extend the tail  150  rearward after launch. 
   Exemplary dimensions of the shaft  170  (exposed portion) for launch from a 12-gauge shotgun shell may include shaft diameter of 0.150 inch and an axial length of 0.50 inch. Similarly, the knob  250  may have an axial length of 0.25 inch and have total radial extension of 0.19 inch. The total length of the plug  240 , shaft  170  and knob  250  may be 1.00 inch. The disk  145  may have a diameter of 0.72 inch and a thickness of 0.003 inch with a 0.193 inch center hole and be composed of a common material, such as paper. 
   Alternatively, the tail  150  and the shaft  170  may form an integral unitary stabilizer that translates rearward from the cup  110  after launch. An example design includes the shaft  170  having a rim lip that extends into the cup  110 . The rim lip possesses a larger diameter than the threaded orifice  210  to prevent ejection from the closure  120  as the integral shaft and tail translate rearward after launch. 
   The liquid payload contained within the bag  130  may include approximately five milliliters (5 ml) of liquid payload. Subsequent to inserting the bag  130  into the cup  110 , two grams (2 g) of epoxy mixed with five grams (5 g) of tungsten powder may be subsequently poured into the remaining space in the cup  110  in order to seal in the payload. Flexane®-80 urethane putty represents a preferred epoxy that can be mixed with diluents to adjust the durometer hardness of the final cured material. 
   The components for the projectile may be combined as the assembly  190  by (a) connecting the shaft  170  to the plug  240 , (b) sliding the tail  150  along the shaft  170  and securing it by the knob  250 , (c) tapping the closure  120  of the cup  110  as a threaded orifice  210  to receive the plug  240  and providing holes  220  along the cup&#39;s cylindrical sides, (d) inserting the bag  130  into the cup  110 , (e) sealing the bag  130  with the cap  180 . The shaft  170  may be designed to enable sufficient longitudinal travel of the tail  150  to provide fin stabilization. Upon assembly, the projectile may be inserted into the shell  260  for ejection from a smoothbore launcher towards an intended target. 
     FIGS. 3A and 3B  show perspective views of the assembly  190  with the tail  150  in stowed and deployed positions, respectively.  FIG. 3A  identifies the cup  110  with the through-holes  220  shown.  FIG. 3B  shows the shaft  170  extending from the threaded orifice  210  at the cup&#39;s aft end (without the optional spring) identifies the cup  110  with the through-holes  220  shown. During flight, aerodynamic drag against the fins  165  induces the tail  150  to move aft along the shaft  170  relative to the assembly  190 . 
     FIG. 4  shows a 12-gauge shotgun shell  260  into which the assembly  190  may be inserted (tail-first) through an opening (at the top) for launch. The shell  260  may be discarded after the assembly  190  has been launched as a projectile to deliver the liquid contained in the bag  130  to the target. Alternatively, the bag  130  can be replaced with a solid fill in the cup  110 , thereby transforming the projectile into a “rubber bullet” with greater targeting accuracy than conventional designs. 
   The assembly  190  may be loaded into a primed 3-inch shotgun shell  260  containing 12 grains of Red Dot smokeless gunpowder from Alliant in Radford, Va. The powder may be disposed above a primer, both opposite the opening (at the bottom). The projectile is secured in the shell  260  with contact cement by coating the cup&#39;s exterior cylindrical wall, immediately loading the assembly  190  into the shell  260 , and allowing the cement to cure before firing. Crimping of the shell  260  is not preferred. The shell&#39;s interior may preferably be sealed to increase combustion pressure from gunpowder burning by the cement that reduces annular gas leakage between the cup  110  and the shell  260  and around the tail  150 . 
   Liquid Payload: The liquid to be delivered in the bag  130  may be composed of materials for use in counter-narcotics interdiction and to provide short-term disabling effects for crowd dispersal or checkpoint control. Under selective police operations, capsaicin and/or other OC-equipped payloads may be considered. Military restrictions on RCA materials encourage development of alternative non-lethal agent, such as a malodorant to produce an identifiably pungent response of the olfactory senses. 
   Tagging the target by a marker represents an alternative technique of non-lethal operation against hostile persons in contrast to dispensing a substance to stimulate a reaction by the target. In particular, the liquid contained in the (clear) bag  130  may include a dye, or alternatively, may provide an opaque emulsion, such as paint, as in the bag  135 . 
   While certain features of the embodiments of the invention have been illustrated as described herein, many modifications, substitutions, changes and equivalents will now occur to those skilled in the art. It is, therefore, to be understood that the appended claims are intended to cover all such modifications and changes as fall within the true spirit of the embodiments.