Hybrid gun barrel

Abstract

A new hybrid gun barrel can be successfully used with modern hotter propellants without unacceptable erosion of the breech section of the gun barrel and while retaining the accuracy and ballistic characteristics of a fully rifled gun barrel. The gun barrel comprises a smooth bore breech section and a longer gain twist rifled muzzle section. The smooth bore breech section can better withstand the high heat and pressure of modern hotter propellants than prior art rifled breech sections. The smooth bore breech section will always be less than one-third the total length of the gun barrel and preferably less than one-fifth the total length of the gun barrel. It can be made of a different material than the rifled muzzle section and can be coated with a material harder than the rest of the gun barrel.

We claim: 
     
       1. A gun barrel having a breech end and a muzzle end, comprising: (a) a smooth bore section at the breech end of the gun barrel; and,   (b) a rifled bore section at the muzzle end of the gun barrel, wherein the pitch of the rifling increases from its beginning nearer the breech end of the gun barrel to its end nearer the muzzle end.   
     
     
       2. The gun barrel according to claim 1, the gun barrel having a total length and the smooth bore section having a length, wherein the length of the smooth bore section is less than one-third the total length of the gun barrel. 
     
     
       3. The gun barrel according to claim 1, wherein the smooth bore section is made of a different material than the rifled bore section. 
     
     
       4. The gun barrel according to claim 1, wherein the smooth bore section is coated with a material harder than the rest of the gun barrel. 
     
     
       5. A gun system, comprising: (a) a gun barrel having a breech end and a muzzle end, including: (i) a smooth bore section at the breech end of the gun barrel; and,   (ii) a rifled bore section at the muzzle end of the gun barrel, wherein the pitch of the rifling increases from its beginning nearer the breech end of the gun barrel to its end nearer the muzzle end; and,     (b) a case telescoped ammunition cartridge.   
     
     
       6. The gun system according to claim 5, the gun barrel having a total length and the smooth bore section having a length, wherein the length of the smooth bore section is less than one-third the total length of the gun barrel. 
     
     
       7. The gun system according to claim 5, wherein the smooth bore section is made of a different material than the rifled bore section. 
     
     
       8. The gun system according to claim 5, wherein the smooth bore section is coated with a material harder than the rest of the gun barrel.