AR-15 Gas Blocks

AR-15 Gas Blocks:


Gas Blocks

Update: November 28 2010. It’s getting hard to keep up with ever changing links from manufacturers and stores. To simplify the process rather than directing visitors to the exact product link I am changing the landing pages to be brand specific rather than part number specific.

The gas block is one of the major components that make up the gas system on which the rifle operates. Without a gas block the AR15 will not cycle. There was a time one there was only one gas block option, that option was the front sight gas block (FSGB). Today its a different world. There’s adjustable gas blocks, low profile gas blocks, railed gas blocks and folding front site gas blocks. The gas blocks are manufactured from aluminum or steel. Steel is preferred for AR15 rifles that will see high round counts.

Note: If you are removing a standard A2 style front sight gas block the pins that fasten it to the barrel must be removed and replaced in a specific direction. Brownells makes a special tool to make this easy and to prevent you from damaging the front site gas block. This tool is called AR-15 Front Sight Bench Block
. See the tool below and click the image to see more information at Brownells.

AR-15 Front Sight Bench Block

Noveske Switchblock Adjustable Gas Block

Adjustable gas block reduces gas flow to ensure reliable function during single-shot operation or when using sound suppression devices. Helps reduce felt recoil and minimize carbon buildup on the bolt carrier and inside the receiver for less frequent cleaning without compromising reliability. Three-position selector drum locks into position and is easily adjusted with the included wrench. Suppressed position reduces excess back pressure to safe levels when using noise limiting devices. Unsuppressed position allows normal weapon operation. Off position enables single-shot operation, preventing spent cartridge ejection while providing a reduced weapon sound signature. Replaces factory gas block, and clamps securely around the barrel with two steel Allen head screws. Gunsmith installation recommended.

Noveske Switchblock Adjustable Gas Block

Troy Industries Low Profile Gas Block


Troy Industries offers a nice low profile set screw mount gas block.

Troy Industries Low Profile Gas Block

JP Enterprises

JP Enterprises has a few gas blocks to offer AR15 shooters.

JPGS-5 Adjustable Low Profile Gas Block

Stainless steel adjustable low profile gas block. Rail-free design allows installation under handguards. Bore .750 View the installation instructions here.


JPGS-2FS Adjustable A2 Gas Block

Stainless steel A2/M4 front sight assembly replaces existing pin-on assemblies and provides a gas adjustment. May also be used as front sight only to extend the sight radius of any existing carbine or rifle.

JPGS-2FS Adjustble A2 Gas Block

JP Adjustable Gas Blocks with Picatinny Rails

JP Adjustable Gas System for AR type rifles. Picatinny rail design allows installation of quick-detach accessories such as front sights, lights and lasers. These gas blocks are available in various bores and materials.

JP Adjustable Gas Blocks with Picatinny Rails

PRI Gas Blocks

PRI has probably the widest range of low profile gas blocks available. The have adjustable, fixed and bores to .936

PRI Low Profile Steel Adjustable Gas Block

The AR15/M16 Steel gas block with ad us table gas porting. This is the same design as the original low profile gas blocks but the addition of some adjustments. The gas block offered in the .750 diameter.

PRI Low Profile Steel Adjustable Gas Block

PRI Low Profile Gas Blocks

These are available in various bores and materials.

PRI Low Profile Gas Blocks

PRI Gas Block with Top Picitinny Rail

This Barrel mounted gas block has a 2 1/2″ top rail same plain as the receiver. The rail is constructed of light wait hard coat aluminum. This gas block weights 2.5oz. Gas block fits over a .750 diameter barrel. Block locks into place with 2 crossbolts the same as our original gas block front sight.

PRI Gas Block with Top Picitinny Rail

PRI Flip Up Front Sight with .750 Crossbolt

PRI Flip Up Front Sight w/ .750″ Crossbolt Design FUFS-B Fits Barrels .750″ dia. M16 M4 and AR15 Eliminates the shadow cast on optical sights mounted on the M16 Flattop receiver Lightweight aluminum top post Low reflection matte black corrosion resistant coatings The sight post locks in the up and the down position Solid 4140 cast steel base with provision for the gas tube an integral part of the unit Accepts any standard retrofit M16 front sight post.

PRI Flip Up Front Sight with .750 Crossbolt

Yankee Hill Machine Gas Blocks

Yankee Hill offers low profile gas blocks similar to the PRI and Troy models. Additional they have a unit that’s similar to an A2 front sight with the sight portion removed. YHM most popular models though are the railed gas blocks which are available with 1-4 rails. Some models include provisions for a sling and feature a bayonet lug.

Yankee Hill Gas Blocks

YHM Specter Gas Block

YHM also manufactures the unique Specter Gas Block. The design of this gas block allows the user to mount forearms that extend beyond the standard gas return system. Providing the inside diameter of the forearm is 1-5/8” or greater. It allows the mounting of our forearms without the removal of your pinned or welded muzzle accessory. This gas block consists of a simple, durable, two-piece design that is mounted by the use of four socket head cap screws. Made from high quality steel and finished with a Mil. Spec. phosphate coating.

YHM Specter Gas Block

Badger Ordnance Low Profile Mk 12 Gas Block

This is an exact replica of the gas manifold used on the Mk 12 SOCOM rifles. Fits rifles with a 3/4” (.75)

Badger Ordnance Low Profile Mk 12 Gas Block

Vulcan Arms Quad Rail Gas Block

Machined, aircraft-grade, aluminum, gas block with picatinny rails attaches easily and lets you mount accessories to three sides. Grit blasted for a durable matte finish and hard-coat anodized as per mil spec 8625.

Vulcan Arms Quad Rail Gas Block

Midwest Industries AR15 Gas Blocks

MI offers a low profile and an upper height machined to the height of an A4 upper receiver.

Midwest Industries Gas Block

Brownells AR15 Gas Blocks

Brownells offers two variations of AR15 gas blocks. The first is typical low profile, the second is a modular approach that allows for adding and removing picatinny rails and a bayonet lug.

ar15 modular gas block

DPMS Panther Arms Quad Rail Gas Block

DPMS produces a nice quad rail gas block with bores to suit most common AR15 barrel outside diameters.

DPMS Panther Quad Rail Gas Block

G.B. Systems AR15 Gas Blocks

Manufacturer information not located.

G.B. Systems AR15 Gas Block

EGW AR-15 Gas Block

Low Profile Provides Clearance For Optics & Free-Float Forend Tubes. Machined aluminum gas block properly directs gas and won’t interfere with optics, accessories, or free-float forend tubes. Installs easily with hex screws.

EGW AR Gas Block

VLTOR Weapon Systems Low Profile Gas Block

VLTOR has some nicely profiled gas blocks available in various bores. With the various rail systems currently being offered for the AR15/M16/M4 weapon system, the Vltor Low-Profile Gas Block is small enough to fit inside most rail systems. These gas blocks are an excellent replacement for the archaic fixed sight tower gas block, which has been the standard since the early 1960’s.

The Vltor Low-Profile Gas Block covers one-inch of the barrel’s surface and is made to the tightest tolerance. These gas blocks are offered in two materials, 4140 carbon steel and 17-4PH stainless steel. The 4140 gas blocks are manganese phosphate (black finish) to match barrels with similar finish. The stainless steel gas blocks are blasted to give a matte gray finish.

All current models are made to fit barrels that feature a .750 or 3/4-inch gas block mounting surface. In 2007, Vltor will offer a gas block that will mount to a .625 or .5/8-inch diameter barrel.

VLTOR Weapon Systems Low Profile Gas Block VLTOR Weapon Systems Low Profile Gas Block