AR9 Billet Upper & Lower Receiver Combo Set

Build your next pistol-caliber carbine on a rock-solid foundation with the AR9 Billet Upper & Lower Receiver Combo Set. This matched set from Miami Shooters Supply is machined from premium aluminum billet, providing superior strength and a precise fit for a reliable AR-15 platform build chambered in 9mm. Whether you’re assembling a dedicated range gun, a competition firearm, or a compact home defense tool, this receiver set delivers the durability and tight tolerances serious builders demand. We ship fast so you can start your project without delay.

Key Features

• Machined from 7075-T6 aluminum billet for maximum durability and a premium finish.
• Matched upper and lower receiver set ensures optimal fit and minimal play between components.
• Features a dedicated 9mm lower with a magazine well designed for Colt-style or Glock-style magazines (specific model required).
• Includes an integrated LRBHO (Last Round Bolt Hold Open) mechanism for reliable function.
• Strictly machined to MIL-SPEC dimensions where applicable for broad parts compatibility.
• Flared magazine well on the lower receiver facilitates faster and smoother magazine changes.

Built For

This AR9 receiver set is built for the experienced shooter or builder who understands the importance of a quality foundation. It’s ideal for constructing a reliable and accurate 9mm PCC for USPSA or IDPA competition, where split-second magazine changes matter. It’s also an excellent choice for a robust home defense firearm or a cost-effective, high-fun-factor range rifle.

Specifications

• Caliber: 9mm Luger (designed for pistol-caliber carbine conversion).
• Material: 7075-T6 Aluminum Billet.
• Finish: Type III Hardcoat Anodized (Black).
• Lower Receiver Compatibility: Designed for Colt or Glock-style 9mm AR magazines (verify model).
• Upper Receiver Compatibility: Uses a standard AR-15 barrel nut and is compatible with most handguards.

FAQ

Is this AR-15 parts set compatible with standard AR-15 triggers and parts?
Yes, the lower receiver uses a standard MIL-SPEC fire control group pocket, so most AR-15 triggers, safeties, and pistol grips will install normally. The upper receiver accepts standard AR-15 charging handles and barrels with a 9mm bolt carrier group.

Does this lower receiver work with Colt or Glock magazines?
This AR9 billet lower is configured for one specific magazine type. You must select the correct model at purchase for either Colt-style metal magazines or Glock-style polymer magazines, as the magwell and ejector are not interchangeable.