5.56 AR 15 Build Kit – 16” Phosphate Barrel (Classic A2 Handguard), 1:7 Twist Rate

With so much “tacti-cool” stuff hitting the black rifle market, there’s nothing wrong with taking a step back and building a truly classic shooter. This Classic AR-15 Build Kit features an old school A2-style upper, complete with an A2 front sight post, A2-style “bird cage” flash hider, and traditional forged M4 flattop upper.

Inside, you’re getting a mil-spec lower parts kit and a chrome-lined M16 bolt carrier group with staked gas key and M4 feed ramps. The 4150 CMV barrel promises MOA accuracy with bomb-proof reliability. A classic M4, six-position buttstock and buffer are included.

What’s Included

This kit is not a firearm. It includes an assembled upper receiver, bolt carrier group, lower parts kit, and buffer assembly with buttstock.

Here’s the beginner’s guide to 80% lowers.

AR-15 Rifle Kit Specs

Barreled uppers are assembled in-house before shipment.

Barrel

• Chamber: 5.56 NATO
• Contour: M4/Government
• Length: 16”
• Twist Rate: 1:7
• Gas System: Mid-length
• Gas Block: A2-type FSB
• Gas Port: 0.750”
• Gas Hole Dia.: 0.070”
• Muzzle Threads: 1/2×28
• Feed Ramps: M4
• Material: 4150 CMV
• Finish: Phosphate
• Process: Button Rifled
• Lining: QPQ Nitride
• Extension: M4
• Muzzle: A2 “Birdcage” Flash Hider

Handguard

• Attachment System: A2 Handguard
• Finish: Matte black
• Top Rail: None
• Material: Polymer
• Attachment: Delta ring

Upper Receiver

• Profile: M4 Flattop
• Material: Forged 7075-T6 Aluminum
• Finish: Type III Hardcoat Anodized (Mil-Spec)

Bolt Carrier Group

• Profile: M16/Full-Auto
• Steel: Carpenter No. 158 (Mil-Spec)
• Exterior: Nitride
• Interior: Chrome-Lined
• Gas Key: Staked, Chrome-lined
• Charging Handle: Included

Lower Receiver Parts

• Buffer System: Mil-spec, Carbine
• Buttstock: Mil-spec, M4-type
• Parts Kit: Mil-spec, single-stage

Lower receiver sold separately. 

WARNING: Handling firearms parts and certain firearm accessories can expose you to lead and other petroleum products known to the State of California to cause cancer and reproductive harm. For more information, visit www.P65Warnings.ca.gov 

Shipping Restrictions 

We cannot ship certain parts and accessories to states that prohibit the sale or ownership of such components, like California, New York, and others. Before ordering, see our shipping restrictions for a list of all prohibited states and locales. We try our best to keep our shipping restrictions current, but state laws change almost daily. It is your responsibility to be aware of your local firearms laws before purchasing from our website or machining a firearm. 

80-Lower.com only ships within the United States. Federal law prevents international shipments of our products.