ADJUSTABLE GAS BLOCK ASSEMBLY FOR A GAS OPERATED SEMI-AUTOMATIC FIREARM
Adjustable gas block assemblies for gas-operated firearms are disclosed along with modes of operation and methods of use. In certain aspects, gas blocks having a vent opening arranged to receive a vent plug are disclosed, the vent plug having an opening along a length thereof to vent high-pressure gas from the gas block. Kits containing multiple vent plugs and, in some instances, gas blocks are also disclosed.
1 . A method of tuning an adjustable gas block assembly of a firearm, comprising:
firing a cartridge in the firearm with the gas block assembly having a first vent plug positioned within a vent opening;
determining whether the firearm properly extracted and ejected the cartridge and chambered a new cartridge or locked a bolt of the firearm in an open configuration;
replacing the first vent plug of the gas block assembly, the first vent plug having an opening extending along a length thereof, with a second vent plug having an opening extending along a length thereof, wherein the opening of the first vent plug has a different hydraulic diameter than the opening of the second vent plug; and
firing a cartridge in the firearm with the gas block assembly having the second vent plug positioned within the vent opening.
2 . The method of claim 1 , wherein the opening of the second vent plug has a smaller hydraulic diameter than the opening of the first vent plug.
3 . The method of claim 1 , wherein the opening of the second vent plug has a larger hydraulic diameter than the opening of the first vent plug.
4 . A gas block assembly for a firearm, comprising:
a gas block defining a barrel opening, a gas tube opening, a passageway extending from the barrel opening to the gas tube opening, and a vent opening intersecting the passageway; and
a vent plug received within the vent opening;
wherein the vent plug has an opening extending along a length of the vent plug and in communication with the passageway so that high-pressure gas communicating with the passageway can pass through the opening in the vent plug and out of the gas block assembly.
5 . The gas block assembly of claim 4 , wherein the vent plug is removably received within the vent opening.
6 . The gas block assembly of claim 4 , wherein the vent plug is threadably received within the vent opening.
7 . The gas block assembly of claim 4 , wherein the vent opening is positioned between the gas tube opening and the barrel opening.
8 . The gas block assembly of claim 4 , wherein the vent opening extends from a forward surface of the gas block rearward to the passageway and wherein the gas tube opening extends from a rearward surface of the gas block forwardly to the passageway.
9 . The gas block assembly of claim 4 , wherein the vent plug has a length sufficient to extend at least partially into the passageway when received within the vent opening.
10 . The gas block assembly of claim 4 , wherein the vent opening has a first cross-sectional dimension adjacent an outer surface of the gas block and a second cross-sectional dimension adjacent the passageway and intermediate the passageway and the first cross-sectional dimension; and
wherein the second cross-sectional dimension is smaller than the first cross-sectional dimension.
11 . The gas block assembly of claim 10 , wherein the vent plug has a first end matching the first cross-sectional dimension and a second end matching the second cross-sectional dimension.
12 . The gas block assembly of claim 10 , wherein a portion of the vent opening having the first cross-sectional dimension of the vent opening is a threaded portion and a portion of the vent opening having the second cross-sectional dimension is free of threads.
13 . An upper assembly for a firearm, comprising:
the gas block assembly of claim 4 ;
an upper receiver; and
a barrel attached to the upper receiver;
wherein the gas block assembly is attached to the barrel.
14 . A firearm, comprising:
the upper assembly of claim 13 attached to a lower assembly.
15 . A kit, comprising:
a first vent plug for a gas block and a second vent plug for the gas block;
wherein the first and second vent plugs each have a length and at least one of the first and second vent plugs has an orifice extending through the length thereof.
16 . The kit of claim 15 , wherein:
the first vent plug has an orifice extending through the length thereof, the orifice having a minimum cross-sectional dimension; and
the second vent plug has an orifice extending through the length thereof, the orifice of the second vent plug having a minimum cross-sectional dimension less than that of the orifice of the first vent plug.
17 . The kit of claim 15 , wherein:
the first vent plug has an orifice extending through the length thereof and the second vent plug is free of an orifice extending through the length thereof.
18 . The kit of claim 15 , wherein:
the length of one of the first or second vent plugs is greater than the other
19 . The kit of claim 18 , wherein:
the longer vent plug is free of an orifice.
20 . The kit of claim 14 , comprising:
a gas block having a vent opening arranged to receive at least one of the first and second vent plugs.