The Spikes Tactical 5.56x45mm NATO Complete AR-15 Upper (brand part number STU5435-MLS) brings Spike’s fully Mil-spec compliant ST-15 Enhanced series, originally built for law enforcement, to shooters at an affordable price. It’s built around a 16-inch, cold hammer forged Mil-spec barrel cut in Spike’s ST Optimum Profile with a 1:7 twist and a black phosphate finish, running on a mid-length gas system with an F-marked A2 front sight base and a .750-inch gas seat. Spike’s Tactical includes its own Mil-Spec M16 bolt carrier group and tops the build with a 12-inch SAR3 free-floating handguard. Since it’s a complete upper, it drops onto any Mil-spec AR-15 lower without requiring an FFL transfer.

Key Specifications

• Chambered in 5.56x45mm NATO.
• Barrel measures 16 inches, cold hammer forged to Mil-spec.
• Rifled at a 1:7 twist.
• Barrel finished in black phosphate.
• Cut in Spike’s ST Optimum Profile.
• Built on a mid-length gas system.
• Uses an F-marked A2 front sight base.
• Gas seat measures .750 inch in diameter.
• Includes a Spike’s Tactical Mil-Spec M16 bolt carrier group.
• Topped with a 12-inch SAR3 free-floating handguard.

Frequently Asked Questions

Does this upper require an FFL transfer? No, a complete upper alone is not a regulated firearm and does not require FFL transfer.

What gas system does this upper use? Mid-length.

What bolt carrier group is included? Spike’s Tactical’s Mil-Spec M16 BCG.

Buy the Spikes Tactical 5.56 16-inch Midlength Complete AR-15 Upper

Spikes Tactical built this upper to bring law-enforcement-grade Mil-spec quality to everyday shooters at a fair price. Everything from the barrel to the BCG is manufactured to Mil-spec standards. Shop more Spikes Tactical parts or browse our full AR-15 uppers selection to complete your build. Order it from our Lubbock, Texas gun shop for fast, reliable shipping.