REXUS UltraBlok Clamp-On AR15 Gas Block

Our UltraBlok Clamp-On Gas Block is a low-profile style that perfectly fits under handguards and provides the superior interface of a clamp-on model. Unlike many competitor clamp-on models with bulky screw heads that contact the inner diameter of some handguards — which throws off barrel harmonics and degrades accuracy — the gas block will NOT contact the inner diameter of even the slimmest handguards.

Now, why does our clamp-on model provide a superior interface compared to the common, and cheap, set-screw gas blocks — for just a few bucks more? Think of how a set-screw design works: As one cranks in the set screws into the bottom of the block, the top of the gas block is pulled tight against the gas port hole, yes, but what happens to the rest of the block? The tightening set screws actually push the rest of the gas block AWAY from contact with the barrel. This is not optimal. With an uneven strike of the gas key on the gas tube, the block could be jarred loose — and when your gas block goes funky, problems arise. Even the original M16 gas block sight tower was installed with taper pins — similar in concept to our clamp-on method — and not the set screw method, chosen only for cheapness.

The clamp-on design of the UltraBlok Gas Block avoids these problems. Our gas block maximizes surface area contact with the barrel and evenly distributes clamping forces around the whole of the gas block journal. Plus, there's no fussing with drilling dimples for the set screws, and it's easier to resell a barrel that hasn't been buggered up with dimpling.

The UltraBlok Gas Block features:
• Low-profile for installation under handguards
• Lightening cuts for a weight of 1.2 ounces
• Three provided 3/32 hex head screws and one gas tube roll pin
• Non-adjustable K.I.S.S. no-nonsense reliability
• Black Nitrided for all-weather durability and rich color
• 4140 ordnance steel
• Sized for use with .750" gas block journals