Dirty Bird AR-15 Multi-Cal Forged Receiver Set

SKU# D018-1 | by Dirty Bird Industries
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Dirty Bird Industries AR-15 Forged Multi-Cal Lower Receiver:

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.

Meticulous Machining

We wanted perfection, so we teamed up with the folks at MVB Industries. MVB, best known for their innovative ARC-X PDW Stock, is one of the industries' best kept secrets. And while we'd love to keep them all for ourselves, we can't talk about the quality of this lower without giving huge props to their team. Lots of companies are known for their creative vision, others are known for their unwavering attention to detail. MVB does both, and they do it very, very well.

A Quality-Control Centered Process

You'll notice that in addition to ATF issued serial numbers, all of the lowers feature a unique identifier machined near the pistol grip interface. This is for tracking each individual unit throughout the production process. This added step allows QC staff to trace any potential quality issues back to an exact machine and a given batch, no matter how long it has been since that unit was produced.

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?

Self-Adjusting Receiver Tensioner

The MCF-A utilizes a spring-loaded plunger to reduce slop between the upper and lower receiver. No more tension screws or accu-wedges.

Dirty Bird Industries AR-15 Stripped Upper Receiver:

The Dirty Bird Industries AR-15 Cerro Forged Stripped Upper Receiver is precision machined to M16/M4 Mil-Spec using top quality Cerro Forgings. They are then finished with a uniform Mil-Spec Type III hardcoat anodizing. These units are quality checked throughout the process to ensure consistent quality from unit to unit.

Builders know that not all mil-spec forged upper receivers are created equal. Sub-par forgings suffer from pitting and structural defects, poor anodizing can result in a purplish or chalky finish that doesn’t last and sloppy matching can result in mis-sized lugs, burrs or other machine marks.

You have Dirty Bird’s word that these uppers will be free from excessive pitting, machined to spec and finished with quality (not purple or chalky) hard coat anodizing.


  • 7075-T6 Aluminum Cerro Forgings
  • M4 Feedramps
  • .250 takedown pin holes
  • Port Door (Dust Cover) and Forward Assist not included

100% American Made

Dirty Bird Industries' Limited Lifetime Warranty

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