Meta Tactical APEX Bullpup Carbine Conversion Kit for Glock 21 Gen 3, 4 & SF (.45)

With Meta Tactical's APEX bullpup carbine conversion kit for the Glock 21 Gen 3, Gen 4 and SF (.45 ACP), the .45 you already own becomes the core of a compact carbine. The kit contains the APEX-Series chassis and a 16-inch precision drop-in barrel tailored to Glock 21 models.

Check your frame before you order. The chassis ships configured for standard Gen 4 frames, and the box includes an interchangeable part that adapts it to Gen 3 and SF models. Two versions are not supported: Gen 2 pistols, and Glock 21 models with full Picatinny rails. Most aftermarket and optics-ready Glock 21 slides work once the optic comes off.

The streamlined bullpup configuration is built for maneuverability. An integrated cheek rest gives you a stable, repeatable cheek weld, and the 6-position stock adjusts for fit. Controls are ambidextrous, covering the mag release, charging handle and shell deflector. It takes AR-15 A2-style flat-top grips and works with suppressor-height sights.

Total kit weight is 3.25 lb plus the pistol. It is offered in Black. Meta Tactical says the APEX is made in the USA and designed to meet federal firearm regulations. Rules for conversion kits change at the state line, so confirm yours; OSS America does not ship to restricted states.