Two piece rail system for firearm

Abstract

A firearm handguard having two identical halves, or half guards, can engage the barrel nut of certain firearms to thereby provide a mounting rail system. The barrel nut attaches the barrel to the receiver. The half guards can be separately positioned in engagement with the barrel nut before fastening them together. The fastening operation can cause the half guards to clamp onto the barrel nut. Alternatively, the front handguard cup of some firearms can prevent the handguard from slipping forward while the rear barrel nut engagement prevents handguard rotation. Free floating variants, however, must clamp onto the barrel nut.

1 . A handguard for a firearm, the firearm comprising a receiver and a barrel nut threaded onto the receiver, wherein the barrel nut comprises a barrel nut sprocket, and wherein the handguard comprises:
 a first half guard comprising a mounting rail, inner engagement, outer engagement, and a means for engaging the barrel nut sprocket wherein the first half guard is semi-cylindrical with the inner engagement and the outer engagement radially opposed to one another, wherein the outer engagement comprises at least one open hole, and wherein the inner engagement comprises at least one threaded hole;   a second half guard identical to the first half guard; and   a plurality of threaded fasteners that pass through the open holes and thread into the threaded holes to thereby attach the first half guard and the second half guard together in a radially opposed arrangement and wherein the threaded fasteners are tightened to thereby clamp the means for engaging the barrel nut sprocket onto the barrel nut sprocket.   
   
   
       2 . The handguard of  claim 1  wherein the barrel nut sprocket comprises a plurality of teeth, wherein the means for engaging the barrel nut sprocket comprises a plurality of indentations that engage the sprocket teeth and prevent the handguard from rotating around the barrel nut. 
   
   
       3 . The handguard of  claim 2  wherein the fasteners are loosened but not removed to release the handguard from the barrel nut sprocket and to thereby render the handguard removable from the firearm. 
   
   
       4 . The handguard of  claim 1  wherein the fasteners are loosened but not removed to release the handguard from the barrel nut sprocket and to thereby render the handguard removable from the firearm. 
   
   
       5 . The handguard of  claim 1  wherein the barrel nut sprocket comprises a plurality of teeth, wherein the means for engaging the barrel nut sprocket comprises a plurality of indentations that engage the sprocket teeth to prevent the handguard from rotating around the barrel nut. 
   
   
       6 . The handguard of  claim 1  wherein the firearm further comprises a front handguard cup and wherein the first half guard further comprises a cup engagement that fits into the front handguard cup to thereby retain the first half guard between the receiver and the front handguard cup. 
   
   
       7 . A handguard for a firearm, the firearm comprising a receiver and a barrel nut threaded onto the receiver, wherein the barrel nut comprises a barrel nut sprocket, and wherein the handguard comprises:
 a first half guard comprising a mounting rail, inner engagement, outer engagement, and a means for engaging the barrel nut sprocket wherein the first half guard is semi-cylindrical with the inner engagement and the outer engagement radially opposed to one another, wherein the outer engagement comprises at least one open hole, and wherein the inner engagement comprises at least one threaded hole;   a second half guard identical to the first half guard;   a plurality of threaded fasteners that pass through the open holes and thread into the threaded holes to thereby attach the first half guard and the second half guard together in a radially opposed arrangement; and   at least one clamping fastener passing through the means for engaging the barrel nut sprocket wherein the means for engaging the barrel nut sprocket clamp onto the barrel nut sprocket when the clamping fastener is tightened and to thereby attach the handguard to the receiver as a free floating handguard.   
   
   
       8 . The handguard of  claim 7  wherein the means for engaging the barrel nut sprocket comprises a sprocket slot that slips over the sprocket to thereby attach the handguard to the barrel nut. 
   
   
       9 . The handguard of  claim 8  further comprising a pin, wherein the first half guard further comprises a pin slot, wherein the barrel nut sprocket comprises a plurality of teeth, wherein the pin fits into the pin slot to thereby engage the teeth and prevent the handguard from rotating on the barrel nut. 
   
   
       10 . The handguard of  claim 7  further comprising a pin, wherein the first half guard further comprises a pin slot, wherein the barrel nut sprocket comprises a plurality of teeth, wherein the pin fits into the pin slot to thereby engage the teeth and prevent the handguard from rotating on the barrel nut. 
   
   
       11 . A handguard for a firearm, the firearm comprising a receiver and a barrel nut threaded onto the receiver, wherein the barrel nut comprises a barrel nut sprocket, and wherein the handguard comprises:
 a first half guard comprising a mounting rail, inner engagement, outer engagement, and a means for engaging the barrel nut sprocket wherein the first half guard is semi-cylindrical with the inner engagement and the outer engagement radially opposed to one another, wherein the outer engagement comprises at least one open hole, and wherein the inner engagement comprises at least one threaded hole;   a second half guard identical to the first half guard; and   a plurality of threaded fasteners that pass through the open holes and thread into the threaded holes to thereby attach the first half guard and the second half guard together in a radially opposed arrangement.   
   
   
       12 . The handguard of  claim 11  wherein the barrel nut sprocket comprises a plurality of teeth, wherein the means for engaging the barrel nut sprocket comprises a plurality of indentations that engage the sprocket teeth and prevent the handguard from rotating around the barrel nut. 
   
   
       13 . The handguard of  claim 12  wherein the fasteners are tapered fasteners and wherein the open holes are oversize and countersunk such that the first half guard and the second half guard pull towards each other as the fasteners are tightened to thereby clamp the handguard onto the barrel nut. 
   
   
       14 . The handguard of  claim 13  wherein the firearm further comprises a front handguard cup and wherein the first half guard further comprises a cup engagement that fits into the front handguard cup to thereby retain the first half guard between the receiver and the front handguard cup. 
   
   
       15 . The handguard of  claim 11  further comprising a pin, wherein the first half guard further comprises a pin slot, wherein the barrel nut sprocket comprises a plurality of teeth, wherein the pin fits into the pin slot to thereby engage the teeth and prevent the handguard from rotating on the barrel nut. 
   
   
       16 . The handguard of  claim 15  wherein the fasteners are tapered fasteners and wherein the open holes are oversize and countersunk such that the first half guard and the second half guard pull towards each other as the fasteners are tightened to thereby clamp the handguard onto the barrel nut. 
   
   
       17 . The handguard of  claim 16  wherein the means for engaging the barrel nut sprocket comprises a sprocket slot that slips over the sprocket to thereby attach the handguard to the barrel nut. 
   
   
       18 . The handguard of  claim 11  wherein the firearm further comprises a front handguard cup and wherein the first half guard further comprises a cup engagement that fits into the front handguard cup to thereby retain the first half guard between the receiver and the front handguard cup. 
   
   
       19 . The handguard of  claim 11  wherein the fasteners are tapered fasteners and wherein the open holes are oversize and countersunk such that the first half guard and the second half guard pull towards each other as the fasteners are tightened to thereby clamp the handguard onto the barrel nut. 
   
   
       20 . The handguard of  claim 11  wherein the means for engaging the barrel nut sprocket comprises a sprocket slot that slips over the sprocket to thereby attach the handguard to the barrel nut.