Phase 5 Weapon Systems Lo-pro Phase5 Lo Pro Gas Block Clamp

The Phase 5 Weapon Systems Lo-Pro Gas Block Clamp is a low-profile AR-pattern gas block designed for builders and tinkerers who want a clean, minimal-height setup on their rifle. If you're running a rifle-length handguard on a carbine-length barrel or just prefer the sleek look of a slim gas block, this clamp-style block delivers the no-fuss functionality you need without the bulk of traditional front sight posts. Built from 4140 chromoly steel and finished in mag phosphate, it's made to handle the rigors of the range or field.

The clamp design uses two tightening screws for secure, repeatable installation on 0.750" barrels—no permanent modifications, no hassle. At just 1.8 ounces, it adds minimal weight to your upper receiver, and its compact footprint (0.90" wide, 1.48" tall) won't crowd your optic or handguard rail. This is a solid choice for AR-15 and AR-10 builds where real estate and aesthetics matter.

Phase 5 backs their work with precision machining and quality materials—the kind of attention to detail that shows up when you strip and clean the gun. Installation is straightforward for anyone comfortable with basic AR assembly, and the two screws included get you started right away. Just note that you'll need a gas tube roll pin if you're doing a full gas system swap; Phase 5 includes one with their gas tubes, but it doesn't come with this block alone.

Key Features

• Low-profile clamp design—minimal height for cleaner aesthetics and improved optic mounting
• Dual-screw clamping system for secure, repeatable positioning without permanent barrel modification
• 4140 chromoly steel with mag phosphate finish—durable and corrosion-resistant
• Lightweight at 1.8 oz—preserves upper receiver balance
• Compatible with 0.750" diameter barrels on AR-pattern rifles
• Includes two installation screws; straightforward assembly for most shooters

Specifications

Frequently Asked Questions

Will this gas block fit my AR-15?

Yes, if your barrel has a 0.750" outside diameter at the gas block location. This covers most standard AR-15 barrels. If your barrel is a different diameter (such as a pencil profile or heavy contour), this block won't clamp properly. Verify your barrel specs before ordering.

What screws and tools do I need to install it?

The block comes with two installation screws. You'll need a hex key or Allen wrench to tighten them securely. No special tools are required beyond what most AR builders already have on hand.

Do I need a gas tube roll pin?

The gas tube roll pin is not included with this gas block. If you're installing a complete gas system, you'll need a roll pin (which Phase 5 supplies with their gas tubes). If you're only replacing the block itself and your existing gas tube is staying in place, check whether a roll pin was already installed.

Can I use this on a carbine-length or rifle-length system?

Yes. The gas block itself is position-agnostic—it clamps to the barrel. Whether your gas tube is carbine-length or rifle-length depends on your barrel and overall build, not the block itself. This clamp works with both setups.