The Obsidian Arms OA-15C2 billet upper receiver is a stripped, USA-made AR-15 upper machined from 7075-T6 aluminum billet (Obsidian Arms part no. OA-15C2-UR-BLK). At 7.2 ounces it is the lightweight version of the line. It is finished in black hard coat anodizing to MIL-A-8625 Type III Class 2. The ejection port is enlarged for big bore calibers such as .450 Bushmaster, .458 SOCOM and .50 Beowulf, and the receiver leaves off the forward assist and ejection port cover. It works with standard AR-15 lowers and barrels, so it suits custom builds.

Key Specifications

• Material is 7075-T6 billet aluminum, a strong alloy that machines to tight tolerances.
• The finish is black hard coat anodized to MIL-A-8625 Type III Class 2, which resists wear.
• Weight is 7.2 ounces, helpful when building to a target rifle weight.
• The ejection port is enlarged for big bore calibers such as .450 Bushmaster, .458 SOCOM and .50 Beowulf.
• The configuration has no forward assist and no ejection port cover, and a removable shell deflector is included.

Frequently Asked Questions

Does it fit a standard AR-15 lower? Yes. Obsidian Arms states it works with any standard AR-15 lower and any standard AR-15 barrel.

Which calibers is the enlarged ejection port for? Obsidian Arms lists big bore calibers such as .450 Bushmaster, .458 SOCOM and .50 Beowulf.

Does it include a forward assist or dust cover? No. It has no forward assist and no ejection port cover, and it includes a removable shell deflector.

Buy the Obsidian Arms OA-15C2 Lightweight Billet Upper Receiver, Stripped

A billet upper with a big bore ejection port is the starting point for a custom heavy-hitting AR-15 build. Order it from our Lubbock, Texas gun shop for fast, insured shipping, and see more AR-15 accessories and parts while you are here.