American Made
Buy Machine Shop Direct
Need Assistance? Call us at 425.530.0837
10.5" 5.56 SDX Mk II Rail Upper
On Target With
Savings Of
Original Price $329.99
Sale Price $179.99
Do you want a low profile pistol upper?

Built around our SDX MkII this upper delivers one of the lowest profile handguards on the market. Perfect for a pistol/SBR or an entry type personal defense weapon. The ballistics of the 10.5" 4150CMV nitrogen stress relieved  we machine in house provides for accurate fire past 100 yards while giving you the size of an AR that will fit in the back seat of your vehicle. This upper in particular is a favorite of law enforcement for their entry teams and full auto builds.

Everything your pistol/SBR should be.

A staple at any full auto demo shoot for Hardened Arms this upper is designed to take a beating and come back for more. Running a 4140 chrome-moly steel barrel nut that has been QPQ'd for added surface rockwell this upper is almost bullet proof. Eating both brass and steel case ammo means you can train all day long without breaking the bank. Whether running a soul crushing muzzle brake or one of our Stingray 5.56 suppressors the handguard ends just back from the muzzle thread shoulder so your muzzle device will be clear of the end of the handguard. M-Loks cut into the rail at 3, 6 and 9 provides mounting room for all your accessories such a vertical foregrip a favorite among SBR shooters.

10.5" 5.56 SDX MkII AR15 Upper Specifications:

  •     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 Nitrogen Stress Relieved 5.56mm Barrel
  •     Air-Gauged, Inspected and headspaced
  •     Chambered in 5.56mm (Will also shoot .223)
  •     10.5" Socom barrel with M4 Extension
  •     .750" barrel diameter at gas block
  •     1/2x28 threaded muzzle/barrel
  •     Low profile gas block
  •     Barrel dimpled to secure gas block
  •     Carbine-Length gas system
  •     A2 flash hider
  •     10" SDX Mk II Hardened Arms Slim Line M-Lok Rail (1.46" Cross Section, 1.3" Inner Diameter)

Fits any mil-spec AR15 lower receiver.

515 Tucker Ave Friday Harbor, WA 98250 |
Phone: 425-530-0837