Primary Arms GLx MD-21s Push Button 21mm Microdot with AutoLive – ACSS-CQB Red Dot Reticle

Primary Arms GLx MD-21s Features and Performance

The Primary Arms GLx MD-21s is a compact red dot optic built for fast target acquisition, durable performance, and practical use on rifles, carbines, and other Picatinny-equipped platforms. With a compact microdot footprint and a rugged aluminum housing, it is a strong option for shooters who want a dependable optic that balances speed, clarity, and everyday usability.

This model uses the ACSS CQB reticle in red, giving shooters more than a basic aiming dot. The reticle is designed to support quick sight acquisition while still offering a refined aiming reference for more deliberate shots. With 12 brightness settings and night vision compatibility, the optic can be adjusted for a wide range of lighting conditions, from bright daylight to lower-light environments.

Built from aluminum with a hardcoat anodized black finish, this optic is designed for regular use while keeping weight manageable at 5 ounces. The compact form factor works well on many rifle and carbine setups, while compatibility with Aimpoint Micro and standard microdot mounting patterns adds flexibility for different mounting solutions and configurations.

A CR2032 3V lithium coin battery powers the optic, and 1/2 MOA click adjustments allow for precise zeroing. The M1913 Picatinny attachment system makes installation straightforward on a wide range of firearms. Its combination of compact size, durable construction, and practical reticle design makes it a solid choice for shooters looking for a capable modern red dot. For more optics and firearm accessories, visit our accessories collection.

To learn more about manufacturer specifications and product information, see Primary Arms’ official product resources.