Aero Complete Upper 5.56 20" A2 Blk

The Aero Precision Complete Upper Receiver 5.56 NATO 20" A2 Barrel is a no-nonsense, rifle-length upper built on the same platform Aero uses in their M16A4 Special Edition complete rifles. If you're assembling an AR-15 from the ground up or swapping uppers, this gives you a proven, mil-spec-style upper receiver paired with a 20-inch barrel and classic A2 sights—all you need to mount onto a lower receiver and add a bolt carrier group and charging handle to get running.

The 20-inch barrel is 5.56 NATO chambered with a 1:7 twist rate, built from 4150 chrome moly vanadium and finished with Aero's QPQ corrosion-resistant treatment. That barrel length and twist rate make this upper naturally suited to full-power rifle cartridges and heavier projectiles across the 5.56 spectrum, whether you're reaching out to distance or running drills at the range. The rifle-length gas system keeps recoil manageable and is a proven design that favors reliability over firerate.

You get the full A2 furniture package: detachable carry handle, A2 front sight block with bayonet lug, and A2-pattern handguard. It's traditional AR ergonomics—not flashy, not modular, just honest iron sights and a profile that's been trusted for decades. Muzzle is fitted with a standard A2 flash hider. Keep in mind this is an upper receiver assembly only; you'll need to source a bolt carrier group and charging handle separately, plus a stripped lower to complete the rifle.

Build quality from Aero Precision is straightforward and held to spec. This upper works well for hunters, long-range shooters, and anyone who values simplicity and durability over modularity.

Key Features

• 20-inch 5.56 NATO barrel, 1:7 twist, rifle-length gas system
• 4150 chrome moly vanadium barrel with QPQ corrosion-resistant finish
• A2 front sight block with bayonet lug and pinned front sight
• Detachable A2 carry handle for backup sights
• Rifle-length A2 handguard
• Standard A2 flash hider
• Complete upper receiver assembly—BCG and charging handle not included

Specifications

Frequently Asked Questions

What's not included with this upper receiver?

The bolt carrier group (BCG) and charging handle are not included. You'll need to purchase those separately, as well as a stripped lower receiver to complete your rifle.

What lower receiver does this upper work with?

This is a standard M4 upper receiver and will work with any AR-15 lower receiver designed for 5.56 NATO or .223 Remington.

Is this upper good for long-range shooting?

The 20-inch barrel with a 1:7 twist rate is well-suited to distance work, especially with heavier 5.56 projectiles. The rifle-length gas system provides reliable cycling and manageable recoil for accuracy-focused shooting.

Can I remove or replace the A2 front sight block?

The front sight block is pinned. We don't have details on removal or replacement compatibility, so contact Aero Precision directly if you're planning modifications.