Precision Reflex Mk12 Mod 0 Spr Gen Iii 5.56Mm 18'' Bbl 1-7 Twist Upper Fde

The Precision Reflex Mk12 Mod 0 SPR Gen III 5.56mm upper receiver brings proven designated marksman rifle performance to your AR platform build. This complete upper combines a precision 18-inch Douglas 416 stainless steel barrel with a 1-7 twist rate, a flat-top receiver, and rifle-length components that work together to deliver reliable accuracy and control for mid-range engagements. Whether you're building a semi-custom SPR for precision shooting or upgrading an existing lower, this upper gives you the quality barrel and gas system tuning that serious shooters expect from a purpose-built upper.

The included Gen III rifle-length carbon fiber free float forearm decouples the barrel from external pressure, supporting consistent accuracy shot to shot. A full-length top rail with removable PEQ II section gives you mounting flexibility for optics, lasers, or lights. The gas system runs rifle-length tubing paired with a flip-up front gas block front sight, keeping your rifle controllable and on target. A Gas Buster charging handle with an oversized latch makes operation smooth and reliable, especially under gear or in adverse conditions.

This upper ships in Flat Dark Earth finish and arrives with a fitted full-auto bolt carrier and brake/collar assembly, so you're ready to mate it to your lower and get to the range. The Mk12 Mod 0 platform has earned respect in both military and civilian precision shooting communities—this upper lets you tap into that heritage without the custom gunsmith markup.

Key Features

• 18-inch Douglas 416 stainless steel barrel with 1-7 twist for 5.56mm ammunition
• Flat-top receiver with full-length picatinny rail and removable PEQ II section
• Gen III rifle-length carbon fiber free float forearm for barrel harmonics and accuracy
• Rifle-length gas system with flip-up front gas block front sight
• Fitted full-auto bolt carrier included
• Gas Buster charging handle with large latch for reliable cycling
• Brake and collar assembly included
• Flat Dark Earth (FDE) finish

Specifications

Frequently Asked Questions

What lower receiver does this upper fit?

This is a standard AR-15 pattern upper receiver and will mate with any standard AR-15 lower receiver. The flat-top design accepts standard mil-spec lower parts.

Is this upper complete and ready to shoot?

Yes. The upper comes fully assembled with a fitted full-auto bolt carrier, brake, and collar. You'll need to pair it with a stripped or complete lower receiver to create a functional rifle.

What ammunition does the 1-7 twist rate stabilize?

The 1-7 twist rate is optimized for 5.56mm NATO and will stabilize a broad range of bullet weights within that caliber, making it a versatile choice for both training and precision applications.

Can I remove the PEQ II rail section?

Yes. The full-length top rail includes a removable PEQ II section, giving you options to configure your rail space based on your optic and accessory needs.