Firearm with redundantly-identifiable projectiles

Abstract

In a rifle or handgun, identification grooves, which are shallower than the rifling grooves, are formed in a pattern unique to a particular gun, providing a means of identifying the gun through which a bullet was shot. This identification can be used by forensic labs to tie a fired bullet to a gun having a particular serial number, even if the gun is not available for examination. The data mechanically encoded preferably include redundant bits which provide error control coding, thereby making identification both easier and more certain. The pattern is preferably formed by a mechanically-invariant process (such as EDM or photoengraving).

What is claimed is:  
     
         1 . A firearm, comprising: 
 a barrel which is capable of directing a bullet toward a target, the interior surface of said barrel including both 
 rifling grooves to impart spin to the bullet as the bullet traverses the length of said barrel and  
 coding grooves, which are not as deep as said rifling grooves, which provide identifying marks on a bullet shot through said barrel;  
   wherein said identifying marks include error control coding.    
     
     
         2 . The firearm of    claim 1   , wherein said primary grooves are at least about three times deeper than said secondary grooves.  
     
     
         3 . The firearm of    claim 1   , wherein said markers are grooves.  
     
     
         4 . A firearm, comprising: 
 a barrel which is capable of directing a bullet towards a target;    a framework which connects to and supports said barrel;    a chamber, adjacent one end of said barrel, capable of receiving and supporting a cartridge; and    an action, connected to said framework, which can be used to load, fire, and extract the cartridge;    wherein the interior surface of said barrel comprises markers which provide identifying marks, including error control coding, on bullets shot through said barrel;    whereby bullets shot from said barrel are more easily identifiable as having come from said barrel.    
     
     
         5 . The firearm of    claim 4   , wherein said firearm is a rifle and said framework is a receiver.  
     
     
         6 . The firearm of    claim 4   , wherein said firearm is a handgun and said framework is a frame.  
     
     
         7 . The firearm of    claim 4   , wherein said primary grooves are at least about three times deeper than said secondary grooves.  
     
     
         8 . The firearm of    claim 4   , wherein said markers are grooves.  
     
     
         9 . A firearm, comprising: 
 a barrel which is capable of directing a bullet towards a target;    a framework which connects to and supports said barrel;    a chamber, adjacent one end of said barrel, capable of receiving and supporting a cartridge; and    an action, connected to said framework, which can be used to load, fire, and extract the cartridge;    wherein the interior surface of said barrel comprises lands separated by primary grooves, said lands containing secondary grooves which are shallower than said primary grooves;    whereby said primary grooves impart spin to the bullets shot from said barrel and said secondary grooves impart identifying striations, including error control coding, to the bullets shot through said barrel.    
     
     
         10 . The firearm of    claim 9   , wherein said firearm is a rifle and said framework is a receiver.  
     
     
         11 . The firearm of    claim 9   , wherein said firearm is a handgun and said framework is a frame.  
     
     
         12 . The firearm of    claim 9   , wherein said primary grooves are at least about three times deeper than said secondary grooves.  
     
     
         13 . The firearm of    claim 9   , wherein said markers are grooves.  
     
     
         14 . A method of fabricating a firearm, comprising the steps of: 
 (a.) forming a barrel having a predetermined length and a predetermined internal diameter;    (b.) forming primary spiral grooves on the inside surface of said barrel, said primary spiral grooves being capable of imparting torque to a bullet shot through said barrel;    (c.) forming secondary grooves on the inside surface of said barrel, said secondary grooves being shallower and narrower than said primary spiral grooves, said secondary grooves being in a location and of a depth to mark a bullet shot through said barrel;    wherein said secondary grooves encode a unique identifier for each firearm, and are formed by a mechanically invariant marking operation.    
     
     
         15 . The method of    claim 14   , wherein said unique identifier includes error control coding.  
     
     
         16 . The method of    claim 14   , wherein said secondary grooves are formed by an electronically controlled operation which does not include displacement of metal by a rigid body.  
     
     
         17 . A method of fabricating a firearm barrel, comprising the steps of: 
 (a.) forming a barrel having a predetermined length and a predetermined internal diameter;    (b.) forming primary spiral grooves on the inside surface of said barrel, said primary spiral grooves being capable of imparting torque to a bullet shot through said barrel;    (c.) forming secondary grooves on the inside surface of said barrel, said secondary grooves being shallower and narrower than said primary spiral grooves, said secondary grooves being in a location and of a depth to mark a projectile fired by said barrel;    wherein said secondary grooves encode a unique identifier which includes error control coding bits.    
     
     
         18 . The method of    claim 17   , wherein said unique identifier includes error control coding.  
     
     
         19 . The method of    claim 17   , wherein said secondary grooves are formed by an electronically controlled operation which does not include displacement of metal by a rigid body.  
     
     
         20 . A method of fabricating a firearm, comprising the steps of: 
 (a.) forming a barrel having a predetermined length and a predetermined internal diameter;    (b.) forming spiral grooves on the inside surface of said barrel, said spiral grooves being capable of imparting torque to a bullet shot through said barrel;    (c.) forming marking elements on the inside surface of said barrel, said marking elements being configured to mark a bullet shot through said barrel in a redundantly identifiable manner.    
     
     
         21 . The method of    claim 20   , wherein said unique identifier includes error control coding.  
     
     
         22 . The method of    claim 20   , wherein said secondary grooves are formed by an electronically controlled operation which does not include displacement of metal by a rigid body.  
     
     
         23 . A method of evaluating the gun from which a bullet fragment was fired, comprising the steps of: 
 (a.) mounting said bullet fragment on a microscope;    (b.) examining said bullet for striations caused by intentionally introduced markers in the gun from which said bullet was fired;    (c.) determining a binary code, including error control coding, formed by said striations;    (d.) using said binary code to evaluate the possibility of said bullet fragment having been shot from a particular gun.    
     
     
         24 . A method of evaluating the gun from which a bullet fragment was fired, comprising the steps of: 
 (a.) recovering encoded striagraphic identification data from said bullet;    (b.) decoding said striagraphic identification data; and    (c.) looking up said striagraphic identification data in at least one database of unique identification data emplaced in weapons before sale.