Projectile and method for sealing a projectile in a barrel

Abstract

A weapon ( 104 ) including a stock, a barrel assembly ( 105 ) slidably mounted on said stock whereby, on discharging said weapon, the barrel assembly ( 105 ) slidably recoils relative to said stock, and a damper ( 107 ) for decelerating the recoiling barrel assembly, wherein said barrel assembly ( 105 ) includes a plurality of projectiles axially disposed within a barrel ( 108 ) wherein each of said projectiles is associated with a discrete propellant charge for propelling said projectile from the barrel. Suitably the weapon further includes a breech block ( 109 ) which slidably recoils relative to said stock and a further damper ( 106 ) for decelerating the recoiling breech block.

1 . A projectile for a barrel assembly containing multiple projectiles, having a spine and an expandable collar surrounding the spine, whereby when in the barrel, upon rearward movement of the spine with respect to the collar, complementary portions of the spine and the collar interact to expand the collar to form a seal with the bore of the barrel.  
   
   
       2 . A projectile as in  claim 1  wherein the complementary portions of the spine and the collar include substantially conical surfaces tapered towards the rear of the barrel.  
   
   
       3 . A projectile as in  claim 1  wherein the projectile has a nose portion and a tail portion and the spine is integral to the projectile between the nose and tail portions.  
   
   
       4 . A projectile as in  claim 1  wherein the collar surrounds the spine between nose and tail portions of the projectile and is retained on the projectile by interaction with the tail portion.  
   
   
       5 . A projectile as in  claim 1  wherein the collar has an outer surface that interacts with the inner surface of the barrel to form the seal.  
   
   
       6 . A projectile as in  claim 3  wherein the tail portion provides a surface for action of a propellant charge to propel the projectile from the barrel.  
   
   
       7 . A method of sealing a projectile in a barrel, including: 
 providing the projectile with a spine, a propellant charge and a collar surrounding the spine,    applying a force to the spine directed axially down the barrel, and    expanding the collar radially on the spine into a sealing contact with the bore of the barrel.    
   
   
       8 . A method according to  claim 7  further including providing the projectile with a tail portion at one end of the spine and locating the propellant charge behind the tail portion.  
   
   
       9 . A method according to  claim 7  further including relaxing the collar to remove the sealing contact when firing the projectile from the barrel.  
   
   
       10 . A barrel assembly having a barrel with a plurality of projectiles aligned nose to tail for sequential firing from the barrel, each projectile having a spine, a propellant charge and an expandable collar surrounding the spine, each collar having been expanded into sealing contact with the bore of the barrel by rearward movement of the spine with respect to the collar, each collar having a relaxed position on the spine for carrying the collar as the projectile leaves the barrel.  
   
   
       11 . A barrel assembly as in  claim 10  wherein the projectiles are spaced apart in the barrel by their respective propellant charges.  
   
   
       12 . A barrel assembly according to  claim 10  further having an ignition system for firing the projectiles sequentially from the barrel.  
   
   
       13 . A method of firing projectiles from a barrel, including: 
 providing each projectile with a spine and a collar surrounding the spine,    aligning the projectiles axially within the barrel with respective propellant charges,    exerting a force down the barrel to move the spines rearwards within their respective collars,    expanding the collars as a result of the respective movement of spines,    forming multiple seals between the collars and the barrel as result of respective expansions, and    firing the projectiles sequentially from the barrel.    
   
   
       14 . A method of firing projectiles according to  claim 13  wherein the force down the barrel is exerted on the projectiles by reaction to firing of the propellant charges.  
   
   
       15 . A method of firing projectiles according to  claim 13  wherein the force down the barrel is exerted before the projectiles are fired.  
   
   
       16 . A method of firing projectiles according to  claim 13  wherein expansion of each collar is caused by interaction between complementary surfaces on the collar and the respective spine.  
   
   
       17 . A method of firing projectiles according to  claim 13  wherein the complementary surfaces are substantially conical and tapered towards the rear of the barrel.  
   
   
       18 . A method of firing projectiles according to  claim 13  wherein the propellant charges are provided between the projectiles and serve to space the projectiles within the barrel.