Faxon .875 Low Profile Gas Block – 3 Screw Mount

The Faxon low profile gas block in .875 is a heavy-barrel-ready upgrade built to keep your AR-10 cycling smoothly under a free-float handguard. Machined from high-strength steel and finished in a corrosion-resistant black luster, this three-screw model is sized for the larger journals that big-bore builds demand. It is compact, tough, and engineered to do exactly one job flawlessly.

What the Faxon low profile gas block is and who it is for

This block is designed to fit barrels with a .875-inch gas journal, the diameter you will find on heavy-profile AR-10 barrels chambered in cartridges like .308 Winchester and 6.5 Creedmoor. If you are building a precision or duty rifle on a bull barrel, this is the block that matches. Its ultra-low-profile silhouette slides beneath nearly every free-float rail, giving you flexibility across build configurations.

Precision shooters, gunsmiths, and DIY builders will value how directly it drops in. The Faxon low profile gas block keeps a large-format gas system clean, simple, and repeatable.

Key features

• Compatible with .875-inch barrel gas journals on heavy-profile AR-10 barrels
• Machined from durable steel with a corrosion-resistant black luster finish
• Ultra-low-profile design for maximum free-float handguard compatibility
• Secured with three steel set screws using a standard Allen key interface
• Compact dimensions of 1.024 inches wide, 1.00 inch deep, and 1.493 inches tall

Specifications and materials

The Faxon low profile gas block is machined entirely from steel, the right material for a component that lives directly over the hottest part of the barrel. The black luster finish adds a clean, corrosion-resistant surface that resists rust and wipes down easily after a long range session. That durability is what separates a block you install once from one you fight with later.

The block measures 1.024 inches wide, 1.00 inch deep, and 1.493 inches tall, so you can confirm rail clearance before assembly. As with Faxon’s other set-screw blocks, a roll pin is not included, since installation relies on the three set screws for a secure hold.

On a big-bore AR-10 build, the gas block quietly determines how reliably the whole rifle runs, so it is not the place to cut corners. Steel construction stands up to the heat soak of heavier cartridges, and the black luster finish adds a clean, corrosion-resistant layer that resists rust from sweat and weather. The ultra-low-profile shape is what lets you run a slim, modern free-float rail without contact, which is exactly the look and feel most builders are after today.

Installation, care, and compatibility

Setup is simple and repeatable. Degrease the .875 journal, position the block over the gas port, align it carefully, and torque the three set screws in a cross pattern with an Allen key. A drop of thread locker guarantees the screws hold under sustained AR-10 recoil. The ultra-low-profile design clears the vast majority of free-float handguards without contact.

Upkeep is easy. A wipe during regular cleaning and an occasional check of the set screws is all it takes. Match this Faxon low profile gas block with a rifle-length gas tube and your gas system is complete. Our full parts and upgrades catalog carries the tubes, pins, and rails to round out the build, and every Faxon part is cut to the same exacting standard.

Dimpling the barrel beneath the set screws is a common practice on precision rifles, giving each screw a positive seat that resists movement under the sharper recoil impulse of a .308 or 6.5 Creedmoor. It is optional, but it adds peace of mind on a gun you intend to shoot hard. Because the block is easy to remove, it also suits builders who like to experiment with gas tubes and suppressors. Sized correctly and torqued properly, it simply disappears and lets the rifle do its job.

For a heavy-barrel AR-10 that needs a slim, reliable gas block, this Faxon low profile gas block earns its place. Ships direct to your door, no FFL required.