Failsafe training firearms and blank firing adapter therefor

Abstract

A modified barrel and vented blank firing adapter for a failsafe firearm suitable for training exercises and in particular for MILES exercises. A preferred modified barrel includes a plurality of blow out apertures spaced about the barrel's longitudinal axis at a location adjacent to a case of a live ammunition cartridge when loaded in the firearm, the blow out apertures venting from the case a substantial portion of combustion gases produced by firing the live ammunition cartridge; a laterally vented blank firing adapter for producing flash at the muzzle upon firing of a blank ammunition cartridge; and a gas port in the barrel sized for admitting to the firearm's cycling gas tube sufficient combustion gases produced by firing the blank ammunition cartridge for implementing cycling operation of the firearm. The laterally vented blank firing adapter preferably includes a cavity for trapping projectile material when a live ammunition cartridge is fired.

1 . A barrel assembly for a firearm, comprising: 
 a longitudinal barrel having a muzzle and at least one opening through said barrel at a location adjacent to a case of a live ammunition cartridge when loaded therein, said at least one opening adapted for venting from the case a substantial portion of combustion gases produced by firing the live ammunition cartridge;    a muzzle plug secured to the barrel at the muzzle, said muzzle plug including a venting passage configured for venting combustion gases produced by firing a blank ammunition cartridge for producing flash at said muzzle; and    a port in said barrel communicating with a cycling gas tube of said firearm, said port sized for admitting to the cycling gas tube sufficient combustion gases produced by firing the blank ammunition cartridge for implementing cycling operation of the firearm.    
   
   
       2 . The assembly according to  claim 1 , wherein: 
 said at least one opening through said barrel comprises a plurality of openings spaced about the longitudinal axis of said barrel.    
   
   
       3 . The assembly according to  claim 2 , wherein: 
 the diameter of said port is greater than the diameter of a gas tube port normally provided in an original equipment barrel for the firearm.    
   
   
       4 . The assembly according to  claim 2 , the firearm being a Colt M4 carbine, wherein: 
 said port has a diameter of approximately  3 / 32  inch.    
   
   
       5 . The assembly according to  claim 2 , wherein: 
 the size of said port and the configuration of said venting passage of said muzzle plug are related to one another for optimizing cycling of the firearm while producing flash at said muzzle when the blank ammunition cartridge is fired by the firearm.    
   
   
       6 . The assembly according to  claim 3 , wherein: 
 said venting passage of said muzzle plug is configured for laterally venting the combustion gases therefrom.    
   
   
       7 . The assembly according to  claim 2 , wherein: 
 said venting passage of said muzzle plug is configured for laterally venting the combustion gases therefrom.    
   
   
       8 . The assembly according to  claim 7 , wherein: 
 said muzzle plug includes a forward wall for preventing longitudinal projection of projectile material therefrom when the live ammunition cartridge is fired by the firearm.    
   
   
       9 . The assembly according to  claim 8 , wherein: 
 said venting passage of said muzzle plug includes a longitudinal passage open at a rear end of said muzzle plug and at least one passage communicating with said longitudinal passage and open along at least one side of said muzzle plug.    
   
   
       10 . The assembly according to  claim 9 , wherein: 
 said muzzle plug includes a cavity in said forward wall communicating with said longitudinal passage for trapping projectile material projected through said longitudinal passage.    
   
   
       11 . The assembly according to  claim 9 , wherein: 
 said longitudinal passage comprises a longitudinal bore of diameter less than the diameter of a bullet of a live ammunition cartridge fired by the firearm.    
   
   
       12 . The assembly according to  claim 7 , wherein: 
 said venting passage of said muzzle plug includes a longitudinal bore open at a rear end of said muzzle plug and two transverse bores intersecting said longitudinal bore and open along opposite sides of said muzzle plug.    
   
   
       13 . The assembly according to  claim 12 , wherein: 
 each of said transverse bores is perpendicular to said longitudinal bore.    
   
   
       14 . The assembly according to  claim 13 , wherein: 
 said transverse bores are aligned with one another.    
   
   
       15 . The assembly according to  claim 14 , wherein: 
 said muzzle plug includes a cavity communicating with said longitudinal bore for trapping projectile material projected through said longitudinal bore.    
   
   
       16 . The assembly according to  claim 12 , wherein: 
 the diameters of said transverse bores are substantially equal to one another.    
   
   
       17 . The assembly according to  claim 12 , wherein: 
 the aggregate cross-sectional area of said transverse bores is at least four times the cross-sectional area of said longitudinal bore.    
   
   
       18 . The assembly according to  claim 12 , wherein: 
 the diameter of each of said lateral bores is approximately 3.2 millimeters and the diameter of said longitudinal bore is approximately 2.2 millimeters.    
   
   
       19 . The assembly according to  claim 12 , wherein: 
 said assembly includes a flash hider secured to said muzzle and about said muzzle plug, said muzzle plug rotationally positioned such that said transverse bores are aligned with respective slots in said flash hider.    
   
   
       20 . A blank firing adapter for a firearm having a barrel with a muzzle, the blank firing adapter comprising: 
 a muzzle plug adapted to be secured to the barrel at the muzzle; and    a venting passage in said muzzle plug configured for laterally venting combustion gases produced by a blank ammunition cartridge fired by the firearm.    
   
   
       21 . The blank firing adapter according to  claim 20 , wherein: 
 said muzzle plug includes a forward wall for preventing longitudinal projection of projectile material therefrom when a live ammunition cartridge is fired by the firearm.    
   
   
       22 . The blank firing adapter according to  claim 21 , wherein: 
 said venting passage of said muzzle plug includes a longitudinal passage open at a rear end of said muzzle plug and at least one passage communicating with said longitudinal passage and open along at least one side of said muzzle plug.    
   
   
       23 . The blank firing adapter according to  claim 22 , wherein: 
 said muzzle plug includes a cavity in said forward wall communicating with said longitudinal passage for trapping projectile material projected through said longitudinal passage.    
   
   
       24 . The blank firing adapter according to  claim 22 , wherein: 
 said longitudinal passage comprises a longitudinal bore of diameter less than the diameter of a bullet of a live ammunition cartridge fired by the firearm.    
   
   
       25 . The blank firing adapter according to  claim 20 , wherein: 
 said venting passage of said muzzle plug includes a longitudinal bore open at a rear end of said muzzle plug and two transverse bores intersecting said longitudinal bore and open along opposite sides of said muzzle plug.    
   
   
       26 . The blank firing adapter according to  claim 25 , wherein: 
 each of said transverse bores is perpendicular to said longitudinal bore.    
   
   
       27 . The blank firing adapter according to  claim 26 , wherein: 
 said transverse bores are aligned with one another.    
   
   
       28 . The blank firing adapter according to  claim 27 , wherein: 
 said muzzle plug includes a cavity communicating with said longitudinal bore for trapping projectile material projected through said longitudinal bore.    
   
   
       29 . The blank firing adapter according to  claim 25 , wherein: 
 the diameters of said transverse bores are substantially equal to one another.    
   
   
       30 . The blank firing adapter according to  claim 25 , wherein: 
 the aggregate cross-sectional area of said transverse bores is at least four times the cross-sectional area of said longitudinal bore.    
   
   
       31 . The blank firing adapter according to  claim 25 , wherein: 
 the diameter of each of said lateral bores is approximately 3.2 millimeters and the diameter of said longitudinal bore is approximately 2.2 millimeters.