Description
Dirty Bird DB9 9mm MP5-Style Billet Lower Receiver
The DB9 MP5 Billet Lower Receiver is an ideal choice for starting your 9mm AR build. Precision machined from a solid block of 7075-T6 billet aluminum and finished with hard-coat black anodizing per Mil 8625 Type 3 Class 2 specifications, you can be sure that this unit is as tough as they come.
This lower receiver accepts most MP5 style small frame pistol caliber magazines in 9mm and the mag well features a beveled feed lip for quick and easy mag swaps. Extensive testing and attention to detail also ensure that your MP5 style magazines will drop free when released. The proprietary magazine catch and ejector is included and pre-installed from the factory.
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 to H&K MP5 factory specifications.
Bolt Carrier Group (BCG) Requirements
You’ll need a BCG which 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 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 guard as those are all included with this lower.
New Frontier Pistol Caliber Billet AR-9/45 Slick Side Upper with LRBHO
- Machined from 7075 T6 aircraft grade billet aluminum
- Matte black hard-coat anodized per Mil 8625 Type 3 Class 2
- Compatible with all standard AR-15 / AR-9 components and most aftermarket parts
- Manufactured to MILSPEC on state of the art CNC equipment for consistent quality parts and exacting tolerances
- Save money by building your own AR-9 rifle or pistol from the ground up exactly the way you want it configured
- Designed to match lines with New Frontier Armory C-9 & C-45 Billet Lower
- Contains integrated Last Round Bolt Hold Open (LRBHO) technology (PATENT PENDING) that reliably holds the bolt open when magazine is empty
- LRBHO feature is designed for lowers that accept Glock style magazines
- **NOTE — This upper is not machined for a gas tube as it is intended for blowback gas systems only
Once assembled the small “hook” end of the wire form in the upper should be pushed up by the follower of an empty Glock magazine which will engage the bolt catch on the last round fired to hold the bolt in the locked position. If it does not engage, or engages before the last round is fired you can make VERY SMALL adjustments by SLIGHTLY bending the “hook” end down to lock faster or up to lock slower. They are set and function checked during assembly with brand new Glock magazines and our standard bolt catches. Because of varying magazine specs, magazine specs changing over the life of the product, different thicknesses of the pad on the bolt catch and other variables, this adjustment may be necessary with your specific parts.
**NOTE: Some rail systems that use anti-rotation tabs may need slight modification to fit this upper. It is designed for flush mounting rails and standard hand guards.
The New Frontier Armory PC Upper (Gen 2) with LRBHO is proudly MADE IN THE USA by hard working American men and women.