The patented Omni-Hybrid lower is a fiberglass-composite polymer over a zinc metal insert. The insert gives the polymer extra strength in the high-pressure locations and the receiver meets and surpasses military pressure and weight-bearing test requirements. This design produces a platform lighter than standard aluminum lower receivers, and its MSRP of $49.95 makes it one of the most affordable AR lowers on the market.

ATI has taken the Omni-Hybrid and assembled an AR pistol...