Buffer and spring assembly for a firearm

Abstract

The present disclosure provides a buffer kit or assembly for an AR-15, M16, M4 carbine, SR-25, AR-10 and LR-308 type firearm with enhanced fatigue resistance. The buffer assembly includes a weighted buffer, a spring, and a buffer tube. The spring is helically shaped and is formed from multiple wire strands. The stranded wire spring has a greater nominal wire diameter, in comparison to prior art single wire springs, and thus the stranded wire spring itself has a smaller internal diameter. The shoulder of the weighted buffer is provided with a reduced diameter to accommodate the smaller internal diameter of the stranded wire spring.

What is claimed is: 
     
         1 . A buffer and spring kit for a firearm comprising:
 (a) a buffer including a buffer housing defining a sleeve portion, a collar portion, and a shoulder portion, wherein the shoulder portion has a first diameter and the sleeve portion has a second diameter smaller than the first diameter, the shoulder portion being located between the sleeve portion and the collar portion; and   (b) a helical spring extending between a first end and a second end, the helical spring being configured for mounting to the buffer such that sleeve portion and shoulder portion can extend within an interior space defined by the helical spring with the first end abutting the collar portion and with the helical spring being in direct contact with the shoulder portion;   wherein the helical spring is formed from at least two strands of wire that are twisted together and wrapped to form the helical spring.   
     
     
         2 . The buffer and spring kit of  claim 1 , wherein the at least two strands of wire includes a first wire strand and a second wire strand formed from the same material. 
     
     
         3 . The buffer and spring kit of  claim 2  wherein the first and second wire strands are each formed from steel wire. 
     
     
         4 . The buffer and spring kit of  claim 1 , wherein the buffer shoulder portion first diameter is less than 0.78 inch. 
     
     
         5 . The buffer and spring kit of  claim 1 , wherein the helical spring defines an internal diameter that is less than the buffer shoulder portion first diameter. 
     
     
         6 . The buffer and spring kit of  claim 1 , wherein the buffer and spring assembly is configured for installation in at least one of an AR-15, 116, M4 carbine, SR-25, AR-10 and LR-308 type rifle. 
     
     
         7 . A buffer and spring assembly for a firearm comprising:
 (a) a buffer including a buffer housing defining a sleeve portion, a collar portion, and a shoulder portion, wherein the shoulder portion has a first diameter and the sleeve portion has a second diameter smaller than the first diameter, the shoulder portion being located between the sleeve portion and the collar portion; and   (b) a helical spring extending between a first end and a second end, the helical spring being mounted to the buffer such that sleeve portion and shoulder portion are within an interior space defined by the helical spring and the first end abuts the collar portion, and such that the helical spring is in direct contact with the shoulder portion;   wherein the helical spring is formed from at least two strands of wire that are twisted together and wrapped to form the helical spring.   
     
     
         8 . The buffer and spring assembly of  claim 7 , wherein the at least two strands of wire includes a first wire strand and a second wire strand formed from the same material. 
     
     
         9 . The buffer and spring assembly of  claim 8  wherein the first and second wire strands are each formed from steel wire. 
     
     
         10 . The buffer and spring assembly of  claim 7 , wherein the buffer shoulder portion first diameter is less than 0.78 inch. 
     
     
         11 . The buffer and spring assembly of  claim 7 , wherein the helical spring defines an internal diameter that is less than the buffer shoulder portion first diameter. 
     
     
         12 . The buffer and spring assembly of  claim 7 , wherein the buffer and spring assembly is configured for installation in at least one of an AR-15, M16, M4 carbine, SR-25, AR-10 and LR-308 type rifle. 
     
     
         13 . A buffer and spring kit for a firearm comprising:
 (a) a buffer including a buffer housing defining a sleeve portion, a collar portion, and a shoulder portion, the shoulder portion having a first outside diameter and being located between the sleeve portion and the collar portion; and   (b) a helical spring extending between a first end and a second end, the helical spring being configured for mounting to the buffer such that sleeve portion and shoulder portion can extend within an interior space defined by the helical spring with the first end abutting the collar portion and with the helical spring being in direct contact with the shoulder portion;   wherein the helical spring includes between  20  and  40  active coils and a free length of between 8.5 and 12.5 inches; and   wherein the helical spring is formed from a first wire, a second wire, and a third wire that are braided together to form a stranded wire, wherein each of the first, second and third wires is a steel wire having a diameter of between 0.042 and 0.052 inch.   
     
     
         14 . The buffer and spring kit of  claim 13 , wherein the first diameter of the shoulder portion is 0.76 inch. 
     
     
         15 . The buffer and spring kit of  claim 14 , wherein the helical spring defines a first internal diameter of 0.756 inch. 
     
     
         16 . The buffer and spring kit of  claim 13 , wherein the helical spring includes about 26.5 active coils. 
     
     
         17 . The buffer and spring kit of  claim 13 , wherein the helical spring has a free length of about 11 inches. 
     
     
         18 . The buffer and spring kit of  claim 13 , wherein the at least two strands of wire includes a first wire strand, a second wire strand, and a third wire strand. 
     
     
         19 . The buffer and spring kit of  claim 18 , wherein the first, second, and third wire strands is formed from 0.045 inch diameter wire. 
     
     
         20 . The buffer and spring kit of  claim 19 , wherein the first, second, and third wire strands are each formed from steel music wire. 
     
     
         21 . The buffer and spring kit of  claim 13 , wherein the helical spring has a constant spring rate of 1.78 pounds per inch. 
     
     
         22 . The buffer and spring kit of  claim 15 , wherein the helical spring has a constant spring rate of 1.78 pounds per inch, a free length of about 11 inches, about 24.5 active coils, and is formed from three strands of 0.045 inch diameter music wire. 
     
     
         23 . The buffer and spring kit of  claim 13 , wherein the buffer and spring kit is configured for installation in at least one of an AR-15, M16, M4 carbine, SR-25, AR-10 and IR-308 type rifle. 
     
     
         24 . The buffer and spring kit of  claim 13 , wherein the stranded wire has a twist pitch of between about 0.43 and 0.52 inch.