The Anvil Arms Mil-Spec Forged Lower Receiver is a standard-dimension AR-15 lower machined from 7075-T6 aluminum forgings. Hard anodized to MIL-A-8625 Type III Class 2 specifications for wear resistance. Matte black finish measures 0.002″ thick with 50-60 Rockwell hardness.

Tolerances held to ±0.005″ on critical pin holes and ±0.003″ on trigger pocket dimensions. Feed ramps are CNC machined to M4 profile with radiused transitions. Lower is marked “MULTI CAL” for caliber flexibility.

Compatible with any mil-spec AR-15 upper receiver. Works with standard trigger groups, buffer tubes, and pistol grips. No modification required for carbine or rifle-length builds. Ships as a stripped lower requiring FFL transfer.

Jake Morrison’s shop notes

Anvil Arms Mil-Spec lower has a magwell cut that runs 0.003" tighter than Colt blueprints – had to stone-buff a Colt mag to drop free. Trigger pin holes consistently measure 0.1545" on the five we inspected. Rear takedown lug pocket depth varies +0.002/-0.001 across lot.

Tested: 1923 rounds bench-cycled. Pocket tolerance measured: within 0.0008″ on this batch. Weight (actual): 15.3 oz on shop scale. Units shipped from Phoenix in May 2026: 50.