MPN: STU5025-S1S / STU5025-S2S / STU5025-S3S / STU5025-S9S


  • Caliber: 5.56 NATO
  • Finish: Type III Class 2 Hardcoat Anodized Finish
  • Upper Receiver: Spike's Tactical Forged M4 Flat Top Upper - Made from 7075-T6 aluminum
  • Handguard: Spike's Tactical Lightweight 12" SAR3 Rail System - Made from 6061-T6 aluminum
  • M4 Feed Ramps: Yes
  • Muzzle Device: Mil-Spec A2 Flash Hider
  • Barrel: 16” 1:7 Twist M4 profile 5.56 NATO Chrome Lined CMV Barrel
  • Muzzle Thread Pattern: 1/2"-28
  • Gas Block: Spike's Tactical .750" Micro Gas Block
  • Gas Tube: Carbine-Length Melonited Gas tube
  • Bolt Carrier Group: Spike's Tactical Mil-Spec M16 Bolt Carrier Group
  • Charging Handle: Mil-Spec Charging Handle
  • High Pressure Tested (HPT) and Magnetic Particle Inspected (MPI)


  • Weight: ~3 lbs. 15 oz.


  • AR-15 lower receiver


  • 1x Spikes Tactical ST-15 LE 16" Upper 5.56 Carbine-Length M4 Barrel w/ SAR3 Rail
  • 3x Rail covers
  • 1x QD swivel


If you want a group of reliable components that will jump start your AR-15 build, Spike’s Tactical has a package for you. The Spikes Tactical Upper ST-15 LE 16" Carbine-Length 5.56 M4 Barrel with SAR3 Rail is an Armorer’s dream come true. This quality group of components will get you well on your way to building a high-quality AR-15 you can be proud of.

When you pick Spikes ST-15 16 Carbine-length Complete Upper Assembly to begin your build, you can be sure the components you’re using are a great value. The ST-15 was born to serve the law enforcement community. It is precision machined from 7075 T6 aluminum and features extended feed ramps for optimum performance. Standard equipment includes a Mil-Spec forward assist as well as a Picatinny top rail. The interior surfaces of this upper are coated with MIL-L-46010 Dryfilm for long lasting lubricity and easy operation.

The Spikes ST-15 16 Carbine-length combination gives you a high quality, pressure tested, M4 profile barrel machined from Chromoly Vanadium alloy. Stress relief and magnetic particle testing promise long life to the shooter and hard chrome chamber and bore linings ensure long lasting accuracy as well as the toughness to stand up to corrosive propellants.

This Spikes Tactical Upper Assembly comes with a Spike’s Tactical SAR3 Rail. The SAR3 is a lighter-weight brother to the BAR rail. While the SAR3 Rail system is a single piece extruded quad rail. The SAR3 comes with low profile rail covers for comfort. With features like integrated quick detach sockets and scalloped rails that add to operator comfort and ease of use you’ll be hard-pressed to find a better quality lightweight hand guard at any price.

When you look at this upper assembly altogether, we’re sure you’ll agree that this is a great value. In this Spikes Tactical ST-15 16 Carbine-length upper package, you get the same high-quality equipment they offer to the tactical use community, whether you’re a weekend shooter or just building a home defense rifle. Everyone gets the same American made quality and value from Spike’s Tactical.

Have a question?

Ask an Expert