LANTAC USA GB750-S Low Profile .750 Gas Block - 4140 Steel - AR-15

The LANTAC USA GB750-S (LA00243) is an ultra low-profile gas block built for AR-pattern rifles with a .750" gas seat diameter. Made from 4140 gun barrel steel and finished in a durable Type M black phosphate coating, this compact gas block is engineered to sit cleanly under slim and free-float handguards where taller factory blocks will not fit. A laser-engraved LANTAC logo marks the body.

The GB750-S uses a two set-screw retention design to lock tightly to the barrel's gas journal, delivering a gas-tight seal and reliable cycling across the duty cycle. At just 0.906" wide and 1.307" tall, it provides maximum clearance for low-profile handguard systems while remaining easy to access for adjustment and removal.

This listing is for the .750" diameter version designed to fit standard AR-15/M16-pattern barrel gas journals. The block ships complete with the hardware needed for installation, including #10-32 x .125" set screws and a gas tube roll pin.

Whether you are building a custom AR, replacing a worn factory block, or running a low-profile free-float handguard setup, the LANTAC USA GB750-S delivers the strength of 4140 steel, the corrosion resistance of a black phosphate finish, and the precision fit LANTAC is known for.