Buffer assembly for firearm reciprocating bolt

Abstract

A buffer assembly for a firearm has a tubular receiver extension. A damper assembly is positioned within the receiver extension adjacent the receiver extension rear end, and a spring is positioned within the receiver extension with the rear end of the spring surrounding the damper assembly. A buffer is positioned within the receiver extension at the opposite end of the spring from the damper assembly. The receiver extension has a liner that surrounds the spring creating a layer between the spring and the receiver extension. The liner may be a friction reducing material such as a polymer material.

We claim: 
     
         1 . A buffer assembly for a firearm compromising:
 a receiver extension having a tubular shape, the receiver extension comprising a rear end, an open front end, an inner surface and an outer surface;   a damper assembly positioned within the receiver extension adjacent the receiver extension rear end;   a spring positioned within the receiver extension, wherein the spring comprises an outer surface, a front end and a rear end, wherein and the spring rear end at least partially surrounds the damper assembly;   a buffer positioned within the receiver extension, wherein the buffer comprises a weight and the spring front end at least partially surrounds the buffer;   a liner at least partially covering the inner surface of the receiver extension, wherein the liner is positioned between at least a portion of the spring outer surface and a portion of the receiver extension inner surface.   
     
     
         2 . The buffer assembly of  claim 1  wherein the buffer further comprises a buffer body and a buffer head. 
     
     
         3 . The buffer assembly of  claim 2  wherein the buffer body comprises a cavity and the weight is positioned within the buffer body cavity. 
     
     
         4 . The buffer assembly of  claim 3  wherein the buffer body cavity comprises an open end and the buffer head is removably connected to the buffer body to enclose the cavity. 
     
     
         5 . The buffer assembly of  claim 2  wherein the buffer body comprises a polymer material. 
     
     
         6 . The buffer assembly of  claim 2  wherein the buffer head comprises aluminum. 
     
     
         7 . The buffer assembly of  claim 1  wherein the spring comprises a coil spring having an inside diameter and an outside diameter. 
     
     
         8 . The buffer assembly of  claim 7  wherein the damper assembly comprises a damper post. 
     
     
         9 . The buffer assembly of  claim 8  wherein the damper post comprises a head section, a central section having an outside diameter and a nose section. 
     
     
         10 . The buffer assembly of  claim 9  wherein a difference between the inside diameter of the spring and the outside diameter of the damper post central section is 0.030 inches or less across the diameter. 
     
     
         11 . The buffer assembly of  claim 9  wherein a difference between the inside diameter of the spring and the outside diameter of the damper post central section is less than 0.010 inches across the diameter. 
     
     
         12 . The buffer assembly of  claim 1  wherein the damper assembly comprises a damper ball. 
     
     
         13 . The buffer assembly of  claim 1  wherein the liner comprises a thermoplastic polymer. 
     
     
         14 . The buffer assembly of  claim 1  wherein the liner has a thickness of between 0.010 and 0.020 inches. 
     
     
         15 . The buffer assembly of  claim 1  wherein the liner has a thickness of between 0.015 and 0.018 inches. 
     
     
         16 . The buffer assembly of  claim 1  wherein the liner comprises a sheet of material rolled into a tubular shape and inserted into the receiver extension such that a seam extends longitudinally along a side of the receiver extension inner surface. 
     
     
         17 . The buffer assembly of  claim 1  wherein the liner comprises a tube. 
     
     
         18 . The buffer assembly of  claim 1  wherein the liner comprises a material that is sprayed onto the receiver extension inner surface. 
     
     
         19 . The buffer assembly of  claim 7  wherein a difference between the outside diameter of the spring and an inside diameter of the liner is 0.030 inches or less across the diameter. 
     
     
         20 . The buffer assembly of  claim 7  wherein a difference between the outside diameter of the spring and an inside diameter of the liner is less than 0.010 inches across the diameter.