WMD NIB-X UPPER RECR 5.56 STRIPPED

Building a reliable AR-15 from the ground up starts with a quality upper receiver, and the WMD NIB-X Upper Receiver for 5.56 is built to last. This stripped upper receiver is forged from 7075 T6 aluminum to mil-spec standards and finished with WMD's proprietary NiB-X coating—a nickel-boron hybrid that goes on both inside and out to deliver exceptional durability and silky-smooth operation. Whether you're assembling a precision rifle for long-range work, a hunting setup, or a duty gun, this receiver gives you a rock-solid foundation without the guesswork.

The NiB-X finish isn't just about looks. That ultra-smooth, hard-wearing surface reduces friction and resists wear from thousands of charge cycles, making it a genuine upgrade over standard anodizing. Combined with the integrated M4 feed ramps, you get reliable feeding across a wide range of ammunition types and loads—critical for hunters and shooters who demand consistency.

As a stripped upper receiver, you'll need to source and install your bolt carrier group, charging handle, and other components, giving you complete control over the build. If you already have a lower receiver and stock, this upper is the key piece to complete your rifle. The forged aluminum construction and mil-spec dimensions ensure compatibility with standard AR-15 parts and accessories.

Key Features

• Forged 7075 T6 aluminum construction to mil-spec standards
• NiB-X coating inside and out for hardness, corrosion resistance, and smooth operation
• M4 feed ramps for reliable feeding across ammunition variations
• Stripped configuration lets you customize the build to your needs
• A3/A4 compatible design

Specifications

Frequently Asked Questions

What do I need to do to finish building this upper receiver?

This is a stripped receiver, so you'll need to source and install a bolt carrier group, charging handle, and handguard to complete the upper. Once those are added and the upper is mated to your lower receiver, you'll have a functioning rifle.

Is the WMD NIB-X Upper Receiver compatible with my AR-15 lower?

Yes, this upper receiver follows standard AR-15 and mil-spec dimensions, making it compatible with any standard AR-15 lower receiver. It is designed to work with both A3 and A4 lower configurations.

What's the advantage of the NiB-X coating?

NiB-X is a nickel-boron hybrid finish applied inside and outside the receiver. It provides exceptional hardness, resists corrosion, and creates an ultra-smooth surface that reduces friction during cycling and improves reliability over time. It's a genuine performance upgrade compared to standard anodizing.

Will this upper receiver work with common 5.56 and .223 ammunition?

Yes. The M4 feed ramps integrated into this receiver support reliable feeding across standard 5.56 NATO and .223 Remington ammunition loads.