Gas piston system for M16/AR15 rifle or M4 carbine systems

1. A firearm, comprising:

a barrel having a port formed through a wall thereof;

a bolt carrier assembly operable to:

transport a cartridge from a magazine to the barrel, and

eject the spent cartridge from the barrel; and

a gas piston system comprising:

a gas block having a port in communication with the barrel port;

an exhaust tube having:

a head at least partially disposed in the gas block and having a port in fluid communication with the gas block port;

a body extending from the head toward a muzzle of the firearm; and

a channel extending from the exhaust tube port through the body; and

a driver movable relative to the gas block between a forward and rearward position and having:

a piston slidable along the gas block;

a stinger closing the channel in the forward position and opening the channel in the rearward position, and

an operating rod operable to push the bolt carrier assembly away from the barrel,

wherein:

the gas block is fastened to the barrel,

the exhaust tube further has a shoe having a coupling, and

the gas piston system further comprises an exhaust block fastened to the barrel and having a coupling engaged with the shoe coupling.

2. The firearm of claim 1 , wherein:

the gas block is fastened to the barrel near a firing chamber, and

the exhaust block is fastened to the barrel near the muzzle.

3. The firearm of claim 1 , wherein:

the shoe coupling has a plurality of lugs, and

the block coupling has a bayonet profile formed therein receiving the lugs.

4. The firearm of claim 3 , wherein:

the shoe coupling further has a flange having a socket,

the block coupling further has a socket, and

the gas piston system further comprises a detent engaged with the sockets.

5. The firearm of claim 1 , wherein:

the driver further has a hilt formed at an interface of the piston and the stinger,

the hilt has a recess forming a portion of a gas chamber, and

the exhaust head has a conical inner surface forming another portion of the gas chamber.

6. The firearm of claim 1 , wherein the gas piston system further comprises a return spring disposed along an outer surface of the operating rod.

7. The firearm of claim 1 , wherein each of the piston and the head have one or more gas rings for engaging an inner surface of the gas block.

8. The firearm of claim 1 , wherein a length of the stinger corresponds to a stroke length of the bolt carrier assembly.

9. A gas piston system comprising:

a gas block for mounting to a barrel of a firearm and having a port for communication with a port of the barrel;

an exhaust tube having:

a head at least partially disposed in the gas block and having a port in fluid communication with the gas block port;

a body extending from the head to a shoe;

the shoe having a coupling; and

a channel extending from the exhaust tube port through the body and the shoe;

an exhaust block for mounting to the barrel and having a coupling engaged with the shoe coupling;

a driver movable relative to the gas block between a forward and rearward position and having:

a piston slidable along the gas block;

a stinger closing the channel in the forward position and opening the channel in the rearward position, and

an operating rod for extending to a bolt carrier assembly of the firearm; and

a gas chamber formed in the gas block between the piston and the head.

10. The gas piston system of claim 9 , wherein:

the shoe coupling has a plurality of lugs, and

the block coupling has a bayonet profile formed therein receiving the lugs.

11. The gas piston system of claim 10 , wherein:

the shoe coupling further has a flange having a socket,

the block coupling further has a socket, and

the gas piston system further comprises a detent engaged with the sockets.

12. The gas piston system of claim 9 , wherein:

the driver further has a hilt formed at an interface of the piston and the stinger,

the hilt has a recess forming a portion of the gas chamber, and

the head has a conical inner surface forming another portion of the gas chamber.

13. The gas piston system of claim 9 , further comprising a return spring disposed along an outer surface of the operating rod.

14. The gas piston system of claim 9 , wherein each of the piston and the head have one or more gas rings for engaging an inner surface of the gas block.

15. A firearm, comprising:

a barrel having a port formed through a wall thereof;

a bolt carrier assembly operable to:

transport a cartridge from a magazine to the barrel, and

eject the spent cartridge from the barrel; and

a gas piston system comprising:

a gas block having a port in communication with the barrel port;

an exhaust tube having:

a head at least partially disposed in the gas block and having a port in fluid communication with the gas block port;

a body extending from the head toward a muzzle of the firearm; and

a channel extending from the exhaust tube port through the body; and

a driver movable relative to the gas block between a forward and rearward position and having:

a piston slidable along the gas block;

a stinger closing the channel in the forward position and opening the channel in the rearward position, and

an operating rod operable to push the bolt carrier assembly away from the barrel,

wherein:

the driver further has a hilt formed at an interface of the piston and the stinger,

the hilt has a recess forming a portion of a gas chamber, and

the exhaust head has a conical inner surface forming another portion of the gas chamber.