Quality AR 15 uppers, AR15 parts, AR-15 rifle manufacturer. Friday Harbor, WA
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7.5" 5.56mm M4 Complete Piston Upper (COMING SOON)
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Original Price $649.99
Your Price $599.99
Out Of Stock
Build your ultimate AR15 with a complete piston driven upper from Hardened Arms. Available at an Introductory price of $599.99 for a limited time. Featuring a forward porting gas block with adjustment screw, a single piece carrier and our 10" Scorpion rail. Enjoy the benefits of an AR15 platform with the reliability and gas system of an AK. The system vents at the gas block rather than gas key of the carrier leaving you with a cleaner running upper. Please note these are available in a very very limited supply as we only received a small shipment from our piston supplier. 

AR-15 Upper Receiver Assembly:
  • Hardened Arms M4 Feed Ramp Flat Top Receiver
  • Black anodized mil-spec finished upper receiver
  • Feed ramps for increased feeding reliability on barrel and upper
  • Laser etched T-Marked upper receiver
  • 4150CMV Mil-Spec 5.56 High End Barrel
  • Black Melonite Finish
  • 1/9 Barrel Twist
  • Chambered in 5.56 NATO (will also fire .223 ammo)
  • 7.5" M4 Profile barrel with M4 Extension
  • .750" diameter at gas block
  • 1/2x28 threaded muzzle/barrel
  • Piston System adjustable forward venting gas block
  • Gas block pinned to barrel for a duty grade build.
  • Pistol length piston system
  • Single Piece Ion Bonded Carrier (complete with bolt head assembly and BCG components)
  • A2 flash hider
  • Hardened Arms 7" Scorpion Free Float Rail
  • Charging Handle

Fits any mil-spec AR15 lower receiver.


Hardened Arms uppers are high end, accurate, head spaced, inspected and test fired prior to shipping. They are built using stringent specs, top quality parts and procedures to ensure maximum reliability and performance.

You are responsible for knowing your state laws regarding barrel lengths, pistol, Short barreled rife restrictions. 20% restocking fees if you can not take delivery due to state restriction. Dealer programs are available on our website. Two year warranty against manufacturer defects. Finishes will wear with use, no warranties apply to finish wear.
515 Tucker Ave, Friday Harbor, WA 98250 | sales@hardenedarms.com
Phone: 425-530-0837