The Mark 12 Mod 0 SPR Upper Receiver from Precision Reflex is a complete, fully tricked out tactical upper that’s ready to attach to the lower of your choice and deliver MOA accuracy. The key to the Mod 0’s impressive accuracy is the free-floated, 18" Douglas barrel of high-grade 416 stainless steel with 1-7" target rifling and M4-type feed ramps. The bolt is custom-fitted to the barrel. The core of the PRI Mark 12 Mod 0 SPR Upper Receiver is a mil-spec forged AR-15 flattop receiver with a standard commercial carrier, so compatibility with a mil-spec (.250" pivot/takedown) lower is no problem. Popular tactical/competition features:

• Rifle-length gas system cuts gas velocity to promote excellent reliability
• Precision Reflex Flip Up sights - elevation (front) & windage (rear) adjustable without tools
• PRI Gas Buster charging handle with an easy-to-grasp oversized latch
• OPS muzzle brake to tame recoil & muzzle rise during rapid fire
• Non-reflective matte black finish on barrel, brake, receiver & forearm
• 5.56x45mm NATO chamber accepts both military & civilian .223 Remington ammunition

Precision Reflex’s Mark 12 Mod 0 SPR Upper Receiver is also fitted with their Gen III Carbon Fiber Rifle Forearm, with plenty of accessory mounting space without applying accuracy-compromising pressure to your MOA barrel. An uninterrupted expanse of Picatinny rail extends from the rear of the receiver to about 3/4 of the way down handguard, with shorter, 3" lengths of Picatinny rail at the front of the ’guard in the 3, 6 and 9 o’clock positions.