Dirty Bird MCF-A Ambidextrous Complete Lower Receiver - D133

Introducing the Dirty Bird Industries Multi-Cal Forged Ambidextrous (MCF-A) Complete Lower Receiver. When evaluating a lower, first priority is making sure the basics are done right.

Start with Quality Forgings

All MCF-A lowers are machined from top-tier 7075 Aluminum Forgings from Cerro Fabricated Products. It is a common misconception that all forgings are created equal. Cerro Fabricated Products has been a leader in precision forging, machining, heat treating and more since 1915.

Practical Improvements

It is one thing to add features to a battle proven design that is over 60 years old. There are some pretty crazy lowers out there, but are they practical? Do they sacrifice reliability? Do they make the lower more difficult to service or upgrade?

Ambidextrous Bolt Catch / Release

The Dirty Bird MCF-A Lower Receiver uses MVB’s patented mechanism that implements an Ambidextrous Bolt Catch / Release with elegance, rather than complexity.

• The mechanism both releases and actuates the bolt catch automatically. If the bolt is already in battery, hitting the lever will raise the bolt catch, enabling you to lock the bolt back. If the bolt is locked-back, hitting the lever will release the bolt. Simple.
• The mechanism is non-interfering, meaning that if the Ambi bolt lever is damaged during hard-use or movement is blocked by debris, the standard bolt catch / release paddle still functions flawlessly.
• The mechanism consists of only 4 proprietary components, all of which are machined from Billet S7 Tool Steel and QPQ Nitrided which means pretty much anything on the lower would break before they do.
• Utilizes zero hex screws. Instead, the Ambi Bolt Catch lever is installed with a standard bolt-catch roll pin. This simplifies things and gives the unit a higher level of serviceability.

Dirty Bird 2-Stage Trigger Group

This trigger assembly takes advantage of a two stage fire control design that has been trusted in both competition and combat roles for decades. The first stage pull weight is adjustable based on the trigger spring being used. The red spring will give you a 1.5lbs first stage pull and the black Extra Power trigger spring yields a heavier 2lb pull. And you can expect a crisp second stage break at 2.5lbs for a total pull weight of 4-5lbs (actual total pull weight may vary ± .5lb). The 5lb total weight gives the operator a greater level of safety and control in high stress environments but with a second stage pull weight of only 2.5lbs, the shooter can also squeeze off long range precision shots with ease.

Dirty Bird AR-15 Enhanced Mil-Spec Carbine Receiver Extension / Buffer Kit

• 7075-T6 Aluminum 6-Position Mil-Spec Receiver Extension (7075-T6 Aluminum is nearly twice as strong as 6061)
• Dirty Bird 17-7 Stainless Steel Flat Wire Spring
  • Enhanced Corrosion Resistance
  • Outlasting Performance
• 4oz H1 Buffer w/ 2 steel and 1 tungsten counter weights
• Hardened Castle Nut w/ Staking Cuts
• Mil-Spec End Plate

Forward Controls Design EMR-A (Enhanced Ambidextrous Magazine Release)

• 4140 Chrome Moly steel magazine catch
• 7075-T3 aluminum lever
• Multi-faceted Control Surface
• Heavy duty roll pin with 800lb shear strength
• Low-profile shaft is 0.03″ shorter than MIL-SPEC
• 10.9 lb high strength magazine catch spring

Sparrow Dynamics LS Ambi Safety Selector

Our ambidextrous safety selector is a superior drop-in replacement for all mil-spec safeties (AR platform 5.56 & 7.62) and is meticulously machined from the finest materials to provide the smoothest operation and a crisp positive feedback. The levers are machined from 7075 aluminum and are hard coat anodize after a heavy acid etch process which dulls the machined surface and provides a superior protective finish. The core or shaft is a hardened 416 stainless steel which is highly corrosion resistant and very strong. Our unique lobular interface between the lever and the shaft provides a solid connection and allows the lever to be installed in 6 different positions (not just two like other safeties) for the the ultimate experience in user customization. The engraved markings on the shaft simplify the installation of the 60 or 90 degree throw options.

Magpul MOE-K2+ Grip

BCMGUNFIGHTER SOPMOD Stock – MOD 0

Made in the USA

Backed by the Dirty Bird Limited Lifetime Warranty

*Limited compatibility with anti-walk / anti-rotation pins. We can confirm compatibility with Dirty Bird Brand Anti-Walk pins.

*Black color is type 3 hard anodized per mil-spec. Other colors will be Cerakote.