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

The Precision Reflex Mk12 Mod 0 SPR Gen II upper receiver in 5.56mm brings proven designated marksman rifle ergonomics and accuracy to your build. Built on the legacy of a platform trusted for precision work, this 18-inch barreled upper with 1-7 twist rate is engineered for shooters who demand a balance of portability and long-range capability. Whether you're setting up a rifle for tactical training, competition, or field use, a quality 5.56 upper like this one gives you the foundation to shoot farther and faster than standard carbine setups.

The Mk12 Mod 0 SPR configuration has roots in military and law enforcement use, and the design translates well to civilian shooters who want a versatile mid-range platform. The 18-inch barrel length strikes a practical middle ground—short enough to handle in tight quarters, long enough to take advantage of the velocity and sight radius needed for precision work. The 1-7 twist rate stabilizes a wide range of 5.56 ammunition loads, giving you flexibility at the reloading bench or the ammo shelf.

This upper is finished in FDE (Flat Dark Earth), a durable, neutral tone that works equally well on the range, in training, or in the field. As an upper receiver assembly, you'll pair it with a compatible lower and your choice of optics, furniture, and accessories to complete your rifle. If you're building a precision 5.56 platform or upgrading an existing one, the Precision Reflex Mk12 Mod 0 SPR Gen II delivers a battle-tested design in a compact, capable package.

Specifications

Frequently Asked Questions

What lower receiver does the Precision Reflex Mk12 Mod 0 SPR upper fit?

This is a standard AR-pattern upper receiver, so it will mate with any mil-spec AR-15 lower receiver. Your lower should be chambered or configured for 5.56mm NATO to match this upper.

Is this upper complete and ready to shoot?

This is an upper receiver assembly. To complete your rifle, you'll need a compatible lower receiver, charging handle, bolt carrier group, and your choice of optics, grips, and furniture.

What is the 1-7 twist rate good for?

The 1-7 twist stabilizes a wide range of 5.56mm loads, from lighter 55-grain rounds to heavier 77-grain ammunition. This twist rate is flexible and forgiving for both standard and match-grade ammunition.

What's the advantage of an 18-inch barrel for a 5.56 rifle?

An 18-inch barrel balances velocity and sight radius with shorter overall length, making it suitable for precision rifle work, designated marksman applications, and shooters who want better handling than a full-length rifle without sacrificing much ballistic performance.