Dirty Bird DB9 9mm MP5-Style Billet Lower Receiver

Dirty Bird DB9 9mm MP5-Style Billet Lower Receiver

The DB9 MP5-Style Billet Lower Receiver is the perfect foundation for your 9mm AR build. Precision CNC-machined from 7075-T6 billet aluminum and finished with durable Mil-Spec Type III Class 2 hard-coat anodizing, this lower delivers exceptional strength and reliability.

Compatible with most MP5-style small-frame 9mm magazines, the magwell features a beveled feed lip for faster reloads. Each unit includes a pre-installed proprietary magazine catch and ejector, ensuring reliable mag retention and consistent drop-free performance.

Other features include:

• Machined from 7075-T6 aircraft-grade billet aluminum
• Matte black hard-coat anodized per Mil 8625 Type 3 Class 2
• Precision-machined magazine well with beveled feed lip for easy mag swaps
• Machined and engraved to be compatible with 45 and 60-degree short-throw fire control selectors, such as the BAD_ASS ST 45 Lever
• Compatible with most standard AR-9 components and most aftermarket parts
• Take down pin spring and detent hole is threaded for a 6-32 set screw for easy capturing (hardware included)
• Upper tension screw behind grip screw (threaded hole with hardware included) to adjust any “slop” out of vertical fit between upper and lower
• Ambidextrous trigger finger rests with grooves (above and below mag release/mag catch)
• Threaded bolt catch pin (Threaded hole and hardware)
• Integrated large opening “winter” trigger guard
• Limited Lifetime Warranty

Important information:

• Magazine Compatibility: The lower was designed to fit and drop free factory MP5 9mm magazines. It has also been thoroughly tested with many aftermarket magazines to fit and drop free. Although it accepts and shoots other aftermarket magazines (KCI, etc), some slight modification may be needed to get them to drop free from this lower because of the varying width measurement we have seen when checking these magazines against H&K MP5 factory specifications.
• Bolt Carrier Group (BCG) Requirements: You’ll need a BCG that is compatible with Glock-style magazines. Some BCGs in the market are compatible with both Colt and Glock-style magazines, but some others are specific. The difference is that Glock magazine-compatible BCGs have the relief cuts necessary to clear the magazines.
• Lower Parts Kit Compatibility: Any mil-spec or better LPK will work but you won’t need the mag catch assembly, bolt catch roll pin, or the trigger guar,d as those are all included with this lower.

Backed by Dirty Bird Industries’ Limited Lifetime Warranty
100% American Made