Billet AR-9 Lower Receiver

For builders seeking a dedicated, high-quality foundation for a 9mm AR pistol or carbine, the Billet AR-9 Lower Receiver from Miami Shooters Supply is the essential starting point. This isn’t a modified AR-15 lower; it’s a purpose-built platform engineered from the ground up for reliable 9mm blowback operation. Crafted from premium 7075-T6 aluminum, it offers superior strength and a precise fit for a tight, rattle-free build, and it ships fast to get your project moving.

Key Features

• Machined from a solid block of 7075-T6 aluminum billet for maximum durability and a clean, aesthetic profile.
• Designed specifically for 9mm, featuring a dedicated magwell for Glock-style magazines (compatibility varies by brand).
• Incorporates a Last Round Bolt Hold Open (LRBHO) mechanism, a critical feature often missing on adapted lowers.
• Hard-coat anodized finish provides excellent corrosion resistance and a uniform, durable surface.
• Includes a threaded bolt catch pin and integrated trigger guard for a simplified, robust assembly process.
• Machined to mil-spec dimensions where applicable, ensuring compatibility with a wide range of AR-15 upper receivers and parts kits.

Built For

This lower is ideal for the practical shooter building a reliable, compact 9mm PDW or pistol for home defense, competition, or recreational use. It’s also perfect for the enthusiast who appreciates the superior rigidity and detailed machining of a billet receiver over a forged alternative, wanting a solid base for a custom showpiece.

Specifications

• Caliber: 9mm Luger (designed for Glock-pattern magazines)
• Material: 7075-T6 Aluminum Billet
• Finish: Type III Hard Coat Anodized (Black)
• Fire Control: Semi-Auto (compatible with standard AR-15 triggers, hammers, and disconnectors)
• Includes: Threaded bolt catch pin and integrated trigger guard. Lower parts kit and buffer system sold separately.

FAQ

Does this AR-9 lower receiver work with any 9mm upper?
It is machined to standard mil-spec dimensions and should pair with most AR-9 dedicated uppers. Always confirm compatibility with your specific upper receiver, as some proprietary systems may require matching components.

What magazines does this lower accept?
This lower is engineered for use with Glock-style 9mm magazines. We recommend testing with your specific magazines, as fit can vary slightly between aftermarket brands and generations.