5.56X45 Nato Assembled Upper Receiver 16'' Bbl Mid-Length Blk

The Aero Precision 5.56 NATO assembled upper receiver gives you a complete, ready-to-pair upper half for your AR15 build. At 16 inches, this barrel strikes the balance many shooters want: handy enough for close-quarters work or hunting in thick brush, yet long enough to wring solid velocity from the 5.56 round. The mid-length gas system cycles softer than carbine-length alternatives, reducing recoil and bolt wear—a real advantage if you're running this upper hard at the range or in the field. Black nitride finish on the barrel resists corrosion and looks clean without the fuss of polishing.

This is a true assembled upper: the barrel, handguard, gas tube, and front sight are all married and ready to go. You're not piecing together five different components. Just mount it to your lower receiver, add a bolt carrier group and charging handle, and you've got a functioning rifle. The M4-style handguard provides a solid mounting platform for accessories, and the pinned front sight base keeps zero rock-solid. The A2 flash hider tames muzzle flash for better low-light shooting and is the mil-spec standard you'll find on thousands of combat-proven rifles.

Aero Precision has built a reputation on tight tolerances and consistent quality at reasonable cost. This upper is no exception—it's the kind of part that works, year after year, whether you're zeroing optics, training, or hunting. Keep in mind you'll need to source your own bolt carrier group and charging handle to complete the upper, but that gives you the flexibility to choose the components that fit your budget and mission.

Key Features

• 16-inch 5.56 NATO barrel with black nitride finish for corrosion resistance
• Mid-length gas system for reduced recoil and smoother cycling
• Pinned front sight base maintains zero without tools
• M4-style handguard ready for rails, lights, or other accessories
• A2 flash hider included; standard mil-spec profile
• Fully assembled and headspaced—ready to pair with your lower receiver

Specifications

Frequently Asked Questions

What do I need to complete this upper into a working rifle?

This assembled upper does not include a bolt carrier group (BCG) or charging handle. You'll need to source those separately to complete your build. Once you have a BCG and charging handle, you can install them into the upper, then mate the whole assembly to your AR15 lower receiver.

Is the barrel already headspaced?

Yes. This upper arrives assembled and headspaced, so you don't need to have a gunsmith check it before use. That's one less step in getting your build complete.

Can I use a carbine-length gas tube instead of mid-length?

This upper is set up with a mid-length gas system. If you need a carbine-length system instead, you'd need to source a different upper or have the gas tube and related components swapped by a gunsmith.

What kind of lower receiver does this fit?

This is a standard AR15 upper receiver, so it will pair with any mil-spec AR15 lower receiver. It's not compatible with AR10 or other large-frame platforms.