Adjustable gas valve for firearm

1 . An adjustable gas valve for use in a firearm gas block having a cylinder and piston in the gas block, the valve comprising:

a valve body configured to associate with the cylinder and having an exhaust port, the valve body including a plurality of inlet orifices rotatably alignable to selectively receive gas pressure flow from a barrel port;

a regulator that adjustably occludes between none and all of the exhaust port;

an internal diffuser stem configured to extend at least partially inside the valve body and having an open end directed toward the piston;

a plurality of radial exhaust outlets leading to an annular chamber positioned adjacent the exhaust port; and

an exhaust passageway operably connecting the open end with the radial exhaust outlets.

2 . The valve of claim 1 , wherein the regulator adjusts by rotation.

3 . The valve of claim 1 , further comprising a spring biased detent configured to hold the regulator in a selected position.

4 . The valve of claim 3 , wherein the detent is biased by a snap ring spring fitted in an annular groove.

5 . The valve of claim 3 , wherein the detent engages splines on another part.

6 . The valve of claim 5 , wherein the splines are on the valve body and the groove is on the regulator.

7 . The valve of claim 5 , wherein the splines are on the regulator and the groove is on the valve body.

8 . The valve of claim 1 , wherein the regulator is configured to occlude the exhaust port outside the valve body.

9 . The valve of claim 1 , wherein the regulator is configured to occlude the exhaust port inside the valve body.

10 . The valve of claim 1 , wherein the valve body includes a plurality of alignable inlet orifices rotatably positionable to vary gas pressure flow from the barrel port.

11 . The valve of claim 10 , wherein the valve body is further alignable to occlude gas pressure flow from the barrel port.