Ar-15 Upper Reciever Assembled Black 5.56Mm

The Sharps Bros. SBUR03 is a fully assembled AR-15 upper receiver in black, built from 7075-T6 billet aluminum and ready to become the foundation of your next build. Unlike stripped receivers that require additional machining or finishing, this upper comes complete with a mil-spec anodized finish, forward assist, and dust cover already installed—meaning you can focus on choosing the barrel, handguard, bolt-carrier group, and charging handle that match your shooting goals.

Whether you're assembling a 5.56 NATO rifle for duty use, a .223 Remington setup for precision shooting, a 300 BLK suppressed build, a 224 Valkyrie varmint rifle, or a 6.5 Grendel mid-range hunter, this upper receiver will accept all of those standard AR-15 cartridges. The design keeps compatibility wide open for barrel and component choices, so you're not locked into any one caliber family. Just note that the ejection port is sized for standard rounds—it won't accommodate large-bore options like 450 Bushmaster, 458 SOCOM, or 50 Beowulf.

Built for reliability and durability, the billet construction and mil-spec finish mean this upper will hold up through training, hunting, and years of shooting. It's a straightforward, no-fuss platform for builders who want a professional-grade foundation without the hassle of assembly or finishing work.

Key Features

• Fully assembled—forward assist and dust cover pre-installed
• 7075-T6 billet aluminum construction with mil-spec anodized finish
• Compatible with standard AR-15 cartridges: 5.56 NATO, .223 Rem., 300 BLK, 224 Valkyrie, 6.5 Grendel
• Accepts all standard AR-15 upper-receiver components and handguards
• Ejection port sized for standard calibers only

Specifications

Frequently Asked Questions

What AR-15 calibers will this upper receiver work with?

The SBUR03 is compatible with 5.56 NATO, .223 Remington, 300 Blackout, 224 Valkyrie, and 6.5 Grendel. The ejection port is sized for these standard-diameter rounds and is not large enough for big-bore calibers like 450 Bushmaster, 458 SOCOM, or 50 Beowulf.

Is this upper receiver fully assembled or do I need to machine or finish it?

This upper comes fully assembled and finished. The forward assist and dust cover are already installed, and the 7075-T6 aluminum body has a mil-spec anodized black finish applied. You'll only need to add a barrel, handguard, bolt-carrier group, and charging handle to complete your build.

What components do I still need to finish an AR-15 build with this upper?

You'll need to source a barrel, handguard, bolt-carrier group, and charging handle. All standard AR-15 components are compatible with this upper receiver.

Can I use this upper receiver with Sharps Bros. lower receivers?

Yes, this upper receiver is designed to work with standard AR-15 lower receivers, including Sharps Bros. lowers and handguards, as well as other mil-spec compatible options.