Patent Publication Number: US-11397072-B2

Title: Piston/rocket projectile with frangible casing

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention pertains to the field of weaponry and, more particularly, to a piston/rocket projectile sed for non-lethal applications. 
     2. Description of the Related Art 
     The use of non-lethal projectiles in weapon systems include the use of frangible projectiles, which are designed to disintegrate upon target impact thereby minimizing penetration of the target. The use of these non-lethal projectiles can often require specialized equipment, meaning that a non-lethal weapon system cannot be used for lethal applications. Weapon launcher systems that are used for lethal applications may employ non-lethal ballistics such as beanbags or rubber projections, but lack the accuracy 
     A launcher system employing a caseless piston/rocket projectile is described in U.S. Pat. No. 8,342,097 titled “CASELESS PROJECTILE AND LAUNCHING SYSTEM” and issued Jan. 1, 2013 presents a launcher having a barrel adapted to receive a projectile with a charge of propellant and a magazine adapted to hold additional projectiles. Each caseless projectile includes a piston shiftably mounted for movement relative to a main body. When propellant in the projectile is ignited, either mechanically or electrically, the propellant forces the piston forward from a retracted position during a period of initial thrust. After the piston moves to a fully extended position, the propellant exits through vent holes to provide an additional thrust for the projectile, while safely discharging pressure from within the projectile. When an electric current is used to initiate a primer and gas-generating solid propellant inside the projectile, electric current passes through the surfaces on the launcher barrel breech or bolt face into the projectile base and then to the primer and propellant. Once the projectile has been launched, no casing is left in the barrel that must be ejected, and the patent describes that reloading an additional projectile becomes relatively easy and the magazine simply pushes an addition projectile into firing position under the influence of a spring. The launcher system of U.S. Pat. No. 8,342,097 describes no means of extraction of the projectile from the barrel, even in the event of a misfire or if the launcher barrel needs to be emptied. 
     Furthermore, upon multiple firings of the launcher system described in U.S. Pat. No. 8,342,097, it has been discovered that carbon fouling occurs in the barrel bolt face. Since the propellant in the projectile is ignited electrically, such fouling reduces the conductivity of the surfaces contacting the projectile base and significantly limits the total number projectile firings that may occur before the weapon will not have a sufficient electrical path to ignite the primer and propellant. The carbon deposit residue from repeated ignitions cakes onto the bolt face to a thickness of up to 0.020 in. (0.5 mm) and is extremely difficult to clean. While not being limited by theory, it is believed that such reside also includes aluminum either from the piston or lower combustion chamber melting and adding a plasma or other byproduct layer with the carbon deposited. As a result, cleaning is difficult under laboratory conditions, and is even more cumbersome in the field. 
     SUMMARY OF THE INVENTION 
     Bearing in mind the problems and deficiencies of the prior art, it is therefore an object of the present invention to provide a non-lethal projectile that may be fired within a launching system which reduces and/or eliminates fouling residue on a bolt face electrode inside the barrel chamber. 
     It is another object of the present invention to provide a non-lethal projectile that may be fired within a launcher system with improved accuracy. 
     A further object of the invention is to provide an apparatus and method of use directed to an electrically energized two stage piston/rocket projectile that captures the majority of ignition debris which may be readily evacuated with each round. 
     It is yet another object of the present invention to provide a method and apparatus that increases the duty cycle and fired projectile round count before operational field cleaning is needed. 
     Still other objects and advantages of the invention will in part be obvious and will in part be apparent from the specification. 
     The above and other objects, which will be apparent to those skilled in the art, are achieved in the present invention which is directed to a projectile for use with a launcher system having a barrel comprising a projectile body having a combustion chamber for propellant, a piston moveable to extend out of a base of the projectile as a result of ignition of propellant in the combustion chamber, and vents for expulsion of combustion products from the ignition of propellant out of the projectile base after initial movement of the piston. A casing is secured to the base of the projectile body, enclosing the piston and vents prior to the ignition of the propellant. A frangible joint is located between the casing and the base of the projectile body such that upon ignition of propellant within the combustion chamber, the piston is forced against the casing and causes the frangible joint to break. The casing is left in the barrel so that after the piston complete exertion of propulsion force against the casing, combustion products of the ignition of the propellant are expelled through the vents out of a lower end of the projectile and solid combustion byproducts from the ignition of the propellant are collected in the casing. 
     The projectile vents may be noncircular and formed in part by wall of an inner surface of the projectile body and in part by an outer surface of the piston. The Projectile body may be formed of an electrically non-conductive material and propellant in the combustion chamber may be ignited electrically. The projectile may further include an electrode extending through the projectile body and into the combustion chamber. The projectile may include a gel-type propellant in the combustion chamber, and the electrode may extend into the gel-type propellant within the combustion chamber. 
     In addition, the projectile may include a nose portion at an end opposite the projectile base, the nose portion may have a rupture capsule disposed in an interior surface of the nose portion. The nose portion may be configured to open the rupture capsule upon contact with a target. The nose portion may include tear joints on an exterior surface to facilitate opening of the rupture capsule. The diameter of the nose portion may be smaller that the projectile body. The projectile may also include a sticky chip on the projectile body so that the sticky chip can adhere to a target upon impact with the projectile. 
     In a related aspect the present invention is directed to a method of launching a projectile from a launcher system having a barrel and a breech comprising providing a projectile body having a combustion chamber for propellant, a piston moveable to extend out a base of the projectile as a result of ignition of propellant in the combustion chamber, and vents for expulsion of combustion products from the ignition of propellant out of the projectile base after initial movement of the piston, as well as providing a casing secured to the base of the projectile body by a frangible joint between the casing and the projectile body base so that the casing encloses the piston and vents prior to the ignition of propellant. The method includes igniting propellant in the combustion chamber, causing the piston to be forced against the casing and causing the joint to break, thereby leaving the casing in the barrel such that after the piston completes exertion of propulsion force against the casing, combustion products of the ignition of propellant are expelled through the vents out of a lower end of the projectile and solid combustion products from the ignition of propellant are collected in the casing. 
     The frangible joint may comprise a flange in one of either the casing or projectile base, secured in a groove in the other of the casing and or projectile base, and wherein the flange may be sheared upon a predetermined force by the piston to separate the casing from the projectile body upon ignition of propellant in the combustion chamber and extension of the piston out of the projectile base. 
     In another aspect the present invention is directed to a projectile for use with a launcher system having a barrel comprising a projectile body having a combustion chamber for propellant, a piston moveable to extend out a base of the projectile as a result of ignition of propellant in the combustion chamber, and vents for expulsion of combustion products from the ignition of propellant out of the projectile base after initial movement of the piston, the vents being formed in part by walls of an inner surface of the projectile body and in part by an outer surface of the piston. The projectile further comprises a casing secured to the base of the projectile body by a joint between the casing and the base of the projectile body, so that the casing encloses the piston and vents prior to the ignition of propellant. Upon ignition of propellant in the combustion chamber, the piston extends such that the vents are exposed before the piston reaches the limit of its travel within the projectile body, whereupon combustion products of the ignition of propellant are expelled through the vents out of the lower end of the projectile. 
     Yet another aspect of the present invention is directed to a method of launching a projectile from a launcher system having a barrel comprising providing a projectile body having a combustion chamber for propellant, a piston moveable to extend out a base of the projectile as a result of igniting of propellant in the combustion chamber, and vents for expelling combustion products from the ignition of propellant out of the projectile base after initial movement of the piston, the vents being formed in part by walls of an inner surface of the projectile body and in part by an outer surface of the piston. The method includes providing a casing secured to the base of the projectile body by a joint between the casing and the base of the projectile body, so that the casing encloses the piston and vents prior to the ignition of propellant. The method further comprises igniting propellant in the combustion chamber, causing the piston to extend, exposing the vents the piston reaches the limit of its travel within the projectile, and expelling combustion products of the ignition of propellant through the vents out of the lower end of the projectile. 
     A further aspect of the present invention is directed to a projectile for use with a launcher system having a barrel comprising a projectile body formed of an electrically non-conductive material having a combustion chamber for propellant, the combustion chamber having a gel-type propellant therein and an electrode extending through the projectile body and into the combustion chamber for electrically igniting the gel-type propellant, a piston moveable to extend out a base of the projectile as a result of ignition of said gel-type propellant in the combustion chamber, and vents for expulsion of combustion products from the ignition of said gel-type propellant out of the projectile base after initial movement of the piston. A casing is secured to the base of the projectile body, which encloses the piston and vents prior to the ignition of the gel-type propellant. A frangible joint is located between the casing and the base of the projectile body such that upon ignition of the gel-type propellant by the electrode in the combustion chamber, the piston is forced against the casing and causes the joint to break, leaving the casing in the barrel. After the piston completes exertion of propulsion force against the casing, combustion products of the ignition of the propellant are expelled through the vents out of the lower end of the projectile and solid combustion byproducts from the ignition of the propellant are collected in the casing. 
     Still another aspect of the present invention is directed to a method of launching a projectile from a launcher system having a barrel comprising providing a projectile body formed of an electrically non-conductive material having a combustion chamber for propellant, the combustion chamber having a gel-type propellant therein and an electrode extending through the projectile body and into the combustion chamber for electrically igniting the gel-type propellant, a piston moveable to extend out a base of the projectile as a result of igniting the gel-type propellant in the combustion chamber, and vents for expelling combustion products from the ignition of the gel-type propellant out of the projectile base after initial movement of the piston. The method includes providing a casing secured to the base of the projectile body, thereby enclosing the piston and vents prior to the ignition of the gel-type propellant. The method further comprises providing a frangible joint between the casing and the base of the projectile body, and igniting the gel-type propellant by use of the electrode in the combustion chamber, thereby forcing the piston against the casing as a result of propulsion force and causing the frangible joint to break, leaving the casing in the barrel such that after the piston completes exerting propulsion force against the casing, expelling combustion products of the ignition of the propellant through the vents out of the lower end of the projectile such that solid combustion byproducts from the ignition of the propellant are collected in the casing. 
     In another aspect the present invention is directed to a projectile for use with a launcher system having a barrel comprising a projectile body formed of an electrically non-conductive material having a combustion chamber for propellant, the combustion chamber having a gel-type propellant therein and an electrode extending through the projectile body and into the combustion chamber for electrically igniting the gel-type propellant, a piston moveable to extend out a base of the projectile as a result of ignition of the gel-type propellant in the combustion chamber, and vents for expulsion of combustion products from the ignition of the gel-type propellant out of the projectile base after initial movement of the piston. A non-electrically conductive layer is located between the gel-type propellant and the end of the chamber opposite the piston, the non-electrically conductive layer covering at least a portion of a width of the combustion chamber. The non-electrically conductive layer has an opening therein through which extends the electrode. An electrically conductive layer covering at least a portion of the width of the combustion chamber is also included, and is disposed between the non-electrically conductive layer and the gel-type propellant so that the electrically conductive layer is in electrical contact with an end of the electrode. Upon ignition of the gel-type propellant by the electrode and electrically conductive layer in the combustion chamber, the piston is forced outward from the lower end of the projectile and subsequently combustion products of the ignition of the gel-type propellant are expelled through the vents out of the lower end of the projectile. 
     The non-electrically conductive layer may cover the entire width of the combustion chamber, or may include projections extending along the sidewalls of the combustion chamber. The electrically conductive layer may cover the entire width of the combustion chamber, or may include a projection extending therefrom in contact with the end of the electrode. 
     A further aspect of the present invention is directed to a method of launching a projectile from a launcher system having a barrel comprising providing a projectile body formed of an electrically non-conductive material having a combustion chamber for propellant, the combustion chamber includes a gel-type propellant therein and an electrode extending through the projectile body and into the combustion chamber for electrically igniting the gel-type propellant, a piston moveable to extend out a base of the projectile as a result of igniting the gel-type propellant in the combustion chamber, and vents for expulsion of combustion products from the ignition of the gel-type propellant out of the projectile base after initial movement of the piston. The method includes providing a non-electrically conductive layer between the gel-type propellant and the end of the chamber opposite the piston, the non-electrically conductive layer covering at least a portion of a width of the combustion chamber, the non-electrically conductive layer having an opening therein through which extends the electrode. The method further comprises providing an electrically conductive layer covering at least a portion of the width of the combustion chamber, the electrically conductive layer disposed between the non-electrically conductive layer and the gel-type propellant in electrical contact with an end of the electrode. The method further includes igniting the gel-type propellant by use of the electrode and electrically conductive layer in the combustion chamber, forcing the piston outward from the lower end of the projectile and subsequently expelling combustion products of the ignition of the gel-type propellant through the vents out of the lower end of the projectile. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The features of the invention believed to be novel and the elements characteristic of the invention are set forth with particularity in the appended claims. The figures are for illustration purposes only and are not drawn to scale. The invention itself, however, both as to organization and method of operation, may bests be understood by reference to the detailed description which follows taken in conjunction with the accompanying drawings in which: 
         FIG. 1  is a side view of the projectile of the present invention. 
         FIG. 2  is a cross-sectional view taken along the A-A axis of  FIG. 1 . 
         FIG. 3  is a bottom view of the projectile of the present invention having the casing removed for clarity. 
         FIG. 4  is a perspective view of the lower inner sleeve of the present invention. 
         FIG. 5  is a cross-sectional view of the projectile as initially loaded within the launching system, including a schematic presentation of the launching system&#39;s circuit diagram. 
         FIG. 6  is a cross-sectional view of the projectile within the launching system after initial ignition of the projectile. 
         FIG. 7  is a cross-sectional view of the projectile within the launching system as the projectile is leaving the launching system. 
         FIG. 8  is an enlarged cross-sectional view of the casing and body configuration of the projectile of the present invention. 
         FIG. 9  is an enlarged cross-sectional view of the casing and body configuration of the projectile after firing of the projectile within the launching system. 
         FIG. 10  is an enlarged cross-sectional view of the projectile ogive section. 
         FIG. 11  is a side view of the electrically non-conductive layer. 
         FIG. 12  is a cross-sectional view taken along the A-A axis of  FIG. 11 . 
         FIG. 13  is a top view of the electrically conductive layer. 
         FIG. 14  is a cross-sectional view taken along the A-A axis of  FIG. 13 . 
         FIG. 15  is a perspective view of an embodiment of the non-lethal projectile of the present invention. 
         FIG. 16  is an enlarged cross-sectional view of the nose of the projectile in  FIG. 15 . 
     
    
    
     DESCRIPTION OF AN EMBODIMENT OF THE INVENTION 
     In describing the embodiment of the present invention, reference will be made herein to  FIGS. 1-16  of the drawings in which like numerals refer to like features of the invention. 
     Certain terminology is used herein for convenience only and is not to be taken as a limitation of the invention. For example, words such as “upper,” “lower,” “left,” “right,” “horizontal,” “upward,” “downward,” or the like, merely describe the configuration shown in the drawings. Indeed, the referenced components may be oriented in any direction and the terminology, therefore, should be understood as encompassing such variations unless specified otherwise. For purposes of clarity, the same reference numbers will be used in the drawings to identify similar elements. 
     Additionally, in the subject description, the words “exemplary,” “illustrative,” or the like, are used to mean serving as an example, instance, or illustration. Any aspect or design described herein as “exemplary” or “illustrative” is not necessarily intended to be construed as preferred or advantageus over other aspects or design. Rather, the use of the words “exemplary” or “illustrative” is merely intended to present concepts in a concrete fashion. 
     The exemplary piston/rocket projectile  40  of the present invention as shown in  FIGS. 1 and 2  includes a cylindrically shaped outer body  60  having an ogive or blunt shaped dome  62  at its nose or front end and a casing  50  secured to body  60  at its opposite, lower or base end to seal the projectile base  61 . Casing  50  has a flat base  59  and on its periphery above the base, an extractor groove  58  and an outer cylindrical extension  54  above the groove. Inserted within body  60  are lower inner sleeve  70  and upper inner sleeve  80 , which each have cylindrically shaped inner surfaces that slidingly receive piston  90 , which may slide therein with a slight interference. Body  60  may be made from any suitable material such as a composite or polymer. Lower inner sleeve  70  may be made from a metal or alloy such as extrudable 6061-T6 aluminum. Upper inner sleeve  80  may be made from a metal or alloy such as steel. Piston  90  may be made from a metal or alloy such as 7075-T6 aluminum. Casing  50  may be made from a metal or alloy such as aluminum or may have a composite construction of a polymer with a metallic insert molded into a plastic casing body with annular ring, as discussed further below. 
     The connection or joint between projectile body  60  and casing  50  is achieved by an interlocking, annular structure comprising a cylindrical extension  64  extending from the lower or rear end of body  60  within an outer cylindrical extension  54  extending up or forward from casing  50 , with the outer diameter of extension  54  being comparable to the outer diameter of projectile body  60 , as shown in  FIGS. 2 and 8 . Outwardly extending body flange  66  and inwardly extending casing flange  56  fit snugly within complimentarily shaped grooves in casing extension  54  and body extension  64 , respectively. The flanges and grooves, positioned adjacent the outer diameter of casing  50  and body  60 , are configured to be able to have a snap fit as they are pushed together during assembly of the casing to the projectile body. While the above flange and groove configuration are preferred, other configurations are not precluded, for example, having the body flange extending inwardly and casing flange extending outwardly. It should be understood by a person skilled in the art that any configuration sealing the casing  50  and the body  60  could be permissible, including acceptance of a flange within an annular channel. 
     Lower inner sleeve  70  is received in a tight fit within the lower portion of outer body  60 . Upper inner sleeve  80  is likewise received in a tight fit within the upper portion of the outer body  60 , and the lower end of sleeve  80  is stepped in with a smaller diameter to fit within the upper end of sleeve  70 . In some embodiments, upper sleeve  80  and lower sleeve  70  may be of a single construction within body  60 . Piston  90  has a cylindrical elongated body sized to slide freely within the inner bore of lower inner sleeve  70  and a cylindrical head  96  of larger diameter sized to slide freely within the inner bore of upper inner sleeve  80 . The cylindrical construction of piston  90  and head  96  is exemplary only, and may be of any construction so that sliding within the inner bore of sleeve  80  is permitted. As depicted in  FIGS. 3 and 4 , channels  72  are formed in the inner surface of lower inner sleeve  70 , for example by extrusion along the entire inner bore thereof, and are enclosed along their length at the upper end in part by the stepped-in portion of upper inner sleeve  80  and at the lower end in part by the outer surface of the elongated body of piston  90 . The channels  72  in the lower portion of sleeve  70  form in cross-section non-circular passageways along approximately one-half of the length of the sleeve  70 . Three of these channels  72  are shown in the example as a “Y” shape equally spaced around the periphery of piston  90 . These lower end channels  72  and the mating portions of the outer wall of the piston  90  elongated body form gas vents, as will be described further below. 
     Combustion chamber  100  as shown in  FIGS. 2 and 5  is formed between the upper end of the interior of upper inner sleeve  80  and the upper end  94  of piston head  96 . Propellant  101  in combustion chamber  100  may be electrically ignited by applying a current from a battery  132  and capacitor  134  power source via a circuit extending along or through the launcher barrel ( FIG. 5 ). As shown in the schematic, one leg of the circuit in the launcher barrel connects via contact  126  with an upper portion of projectile body  60 . A metal electrode  110  or any other suitable conductive means is provided with an exposed outer end portion adjacent ogive  62  that connects to contact  126  and extends inwardly and has a 90-degree turned contact tab that travels through an opening in the forward end of upper inner sleeve  80 . The opposite inner end portion  112  of electrode  110  makes contact with an electronic primer at the forward end of combustion chamber  100 . Electrode  110  may be inserted or molded into body  60 . The other ground leg of the circuit in the launcher barrel includes contact  128  that connects with casing  50 , which is in contact with the lower end  92  of piston  90 . If casing  50  is not made from a metal or alloy, it may have a composite construction of a polymer or similarly non-conductive material with a metallic electrode slug or terminal bridge insert forming contact  128  molded therein and extending from the outer surface of casing base  59  to the casing inner surface  52  for conductivity with the lower end of piston  90 . Because of the use of electrode  110  as the first circuit leg, no electrically insulating coating is needed on piston  90  as part of the ground leg. 
     When projectile  40  is loaded into launcher  120 , ignition of the propellant is achieved by closing switch  130  and discharging the ignition circuit which travels in one leg from a contact  126  in the launcher barrel through electrode  110  and in the other ground leg from a contact  128  in the launcher barrel breech through the casing  50  and piston  90 . For example, a 150V capacitor  134  may be discharged to supply current to energize a primer, such as the Remington ETRONX primer, and ignite the propellant charge in the combustion chamber  100 . It should be understood by those skilled in the art that the use of 150V capacitors to energize Remington ETRONX primers are only one example of providing ignition of a propellant charge within a combustion, and that other ways of providing a propellant charge within a combustion chamber are not precluded. 
       FIG. 6  depicts the initial piston thrust portion of the launch of projectile  40  from launcher  120 . As the propellant explodes, the hot combustion gases  102  force piston  90  downward. Instead of directly contacting the barrel breech face as in U.S. Pat. No. 8,342,097, piston lower end  92  instead contacts casing inner surface  52  and applies force against the casing  50  structure to propel the remainder of the projectile forward. The joint between the projectile body  60  and casing  50  provides a type of shear flange in which column thickness of the joint materials regulates shear strength to control the release of the projectile from the casing at optimal internal pressures. In the embodiment shown in  FIG. 9 , the casing flange  56  is configured to be frangible, i.e., to shear at a desired force substantially along line S, for example, 5 to 8 lbs. of linear force in the direction along the axis of the projectile. The joint may be configured via selection of materials and shape and thickness to achieve any desired separation force. Alternatively, the projectile body flange  66  may be configured to be frangible to shear along line S′. Other frangible geometrical configurations may be used in place of the joint configuration shown herein. For example, the shear flange may be interrupted and extend around only a portion of the circumference of the casing and projectile body, to reduce the force needed to separate the joint. The length of casing  50  relative to the length of projectile body  60  may be increased beyond that shown, so that the height of casing extension  54  may be greater than that depicted in the drawings. Thus, it will be understood by a person skilled in the art that other configurations of releasing a casing from a projectile are not precluded, and the above cited configurations are exemplary. A shear flange might be obsoleted because of retention within the base cap; or might be minimized in elevation to just hold the piston in assembly. 
     After the shear flange S of the joint between casing  50  and projectile body  60  is broken, projectile  40  is free to move forward by virtue of the force applied by piston  90  out of the projectile base  61  against casing  50 , the latter being thrust against and remaining in the breech of the launcher barrel. As the piston initially travels downward and rearward, mechanical force of the piston thrust alone propels the projectile  40 , which initially carries with it the sheared-off casing flange portion  56  of casing extension  54 . As shown in  FIG. 6 , before the piston reaches the limit of its travel, at approximately 90% of the total distance of travel of the piston, the upper or forward end  94  of the piston passes the lower end of upper inner sleeve  80  and reaches the forward end of gas channels or vents  72  formed in lower inner sleeve  70 , which extend to the lower end of projectile body  60 . The exposure of the three channels  72  shown in the “Y” shape around the periphery of piston  90  as the top of piston passes by act as valves for the second stage propulsion of the projectile. Once channels and vents  72  begin to open to the exploding propellant, the combustion products  102  expel out of the lower end of the vents  72  of the projectile, and further expel rocket energy from the ignition charge. Piston  90  continues to move downward until it is fully extended, as shown in  FIG. 7 . Once the piston  90  is fully extended and the piston base  92  lifts off and separates from contact with the casing  50 , the force of the combustion gases  102  out of the base  91  of projectile  40  alone add further force to propel the projectile from the launcher barrel  124 , as shown in  FIG. 7 . For non-lethal rounds, the projectile speed may be in the range of about 300-400 ft./sec. The barrel may have a rifled interior surface to impart twist to the projectile as it moves through during the rocket propulsion stage of launch. 
     With a typical charge of 35 mg of gunpowder, and even if the composition is high in nitrogen-based compounds, there still is produced considerable carbon and other solid combustion residue  104 , which is captured in the defined contained area inside the internal cup shape of broken-off casing  50  as shown in  FIG. 7 . The casing  50  remaining in the launcher barrel breech  122  provides the means to contain and hold the burnt, expelled gunpowder residue  104  of each projectile round, thereby keeping the barrel  120  chamber relatively clean and greatly extending the duty/cleaning cycle of the launcher. 
     As an alternative to the ETRONX primer and propellant system described above, a gel-type explosive may be employed, which combines the primer and main charge of the propellant. In such case, as shown in  FIG. 2 , the primer may be eliminated, the electrode may be surrounded by annular insulator  114 , and the electrode end  112  in combustion chamber  100  may be extended into a gel-type propellant itself to ignite the propellant  101 . 
     In a further modification shown in  FIG. 10 , an electrically non-conductive layer  115  (see also  FIGS. 11 and 12 ) is disposed between the gel-type propellant  101  and the upper end of combustion chamber  100  opposite upper end  94  of piston  90 , and has a central opening  116  for receiving electrode end  112 . Electrically non-conductive layer  115  may be made of a polymer with a thickness of approximately 0.15 in. (0.4 mm) and may form a layer within combustion chamber  100  extending up to the entire width of combustion chamber  100 , and may further extend  117  in a cup shape ( FIGS. 11 and 12 ) along the side walls of combustion chamber  100 . An electrically conductive layer  118  is disposed adjacent electrically non-conductive layer  115  and may similarly extend up to the entire width of the combustion chamber to form a layer between the electrically non-conductive layer and the gel-type propellant  101 . Electrically conductive layer  118 , shown in the form of a metal disk or plate of stainless steel or aluminum of approximately 0.3 in. (0.8 mm) thickness ( FIGS. 13 and 14 ), may have a stamped or otherwise formed projection  119  extending from the center of the surface opposite the propellant to facilitate good electrical contact with end  112  of electrode  110 . Electrically non-conductive layer  115  and side walls  117  form an insulative liner to ensure that the igniting electrical current is transferred directly to the gel-type propellant  101  and not dissipated into the metal walls of the upper portion of inner sleeve  80  surrounding the combustion chamber  100 . Electrically conductive layer or plate  118  ensures that the igniting electrical current is transferred uniformly along the end of the gel-type propellant within the upper end of the combustion chamber and further acts as a pressure-directing shutoff, to ensure that the force of the ignited combustion products is in the direction of piston  90 . 
     The gel-type explosive provides an improvement over gunpowder-type primer and propellant systems because the pressure vs. time curve is flatter. For low velocity projectiles, the ignition thrusts the projectile into the rifling of the barrel with a slower, more uniform combustion rate. As a result of the elimination of the ETRONX primer ignition and the direct contact of the electrode  110  or the electrically conductive disk  118  with the gel propellant  101 , the energy is transferred more rapidly to the piston, thereby increasing efficiency of the piston propulsion stage and increased velocity with less propellant. Additionally, the combustion byproducts are water vapor, hydrogen and reduced solids, so that less residue remains in the barrel and weapon duty cycles is increased. 
     The domed ogive of projectile  40  shown may be further modified in accordance with the intended use of the projectile. While the projectile shown in  FIGS. 1-14  may be employed as a non-lethal projectile with the blunt trauma ogive  62  and body  60 , further modifications may include the additions of a die marker round, as shown in  FIGS. 15 and 16 . Ogive  62 ′ of projectile  40 ′ may house, for example, a ⅜ in. diameter rupture capsule  140  that can hold various marker/paint formulation, as shown in  FIG. 16  in cross-section. As best shown in  FIG. 15 , the nose  62 ′ cover may also be pre-molded with tear joints  142  extending from the tip of the nose down a portion of the side, to aid in opening of capsule  140  upon contact with the intended target. In some embodiments, the die marker nose  62 ′ may have a smaller diameter than that of the body  60 ′ so that the rifling of the launcher barrel does not disturb the perforations  142  during loading and firing of round  40 ′. The die marker round  40 ′ has the same headspace as the blunt trauma jacket  40 , thus permitting interchangeability of rounds  40 , 40 ′ within a single launching system. The different use body jackets  60 ,  60 ′ may be configured to fit over a common combustion assembly of upper inner sleeve  80 , lower inner sleeve  70  and the combustion chamber  100  and piston  90  therein, and to connect the lower end to a common casing  50 . Additionally, other variant body jackets  60 ,  60 ′ may include a sticky chip that will have some electronics with an adhesive to stick to a target, to monitor location thereof. 
     The casing may be headstamped with identifying information such as caliber, round type, manufacturing date and/or other data. The casing also hermetically seals the projectile round from air or water invasive contamination, thus extending the shelf life significantly. 
     Upon activation of a bolt handle, slide, charging handle, or other similar device known in the art, the casing may be extracted at the end of the bolt stroke via a knockout rod and extractor system engaging casing extractor groove  58 . Casing groove  58  or another extractor groove molded or formed into the projectile body or jacket  60  may be used to enable mechanical means to eject a live cartridge that has malfunctioned. 
     The present invention advantageously reduces and/or significantly eliminates fouling residue on a bolt face electrode inside the barrel chamber. The present invention provides the advantage of a method and apparatus that may be used with an electrically energized two stage piston/rocket projectile that captures the majority of the ignition debris and further may be readily evacuated with each round, thereby leaving the chamber with little to no propellant residue. This method and apparatus increases the duty cycle and fired projectile round count before operational field cleaning is needed. In addition, clue to the larger diameter of shearing between the base cap and projectile joint, the present invention offers a more accurate release of the projectile within the launching system. 
     While the present invention has been particularly described, in conjunction with one or more specific embodiments, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art in light of the foregoing description. It is therefore contemplated that the appended claims will embrace any such alternatives, modifications and variations as falling within the true scope and spirit of the present invention.