PRI 18" Mk12 Mod 0 SPR Gen II URG 5.56 1:7 in FDE

$250.00 - $1,729.95
when in-stock, ships from our shop in 3 to 5 days (+/-)

PRI Mk12 Mod 0 SPR Gen II Upper Receiver Group (URG) - FDE

This is the PRI standard configuration URG for the Mark 12 Mod 0 - 18" 1:7 Mark 12 Mod 0 SPR Upper in FDE Finish 5.56 Cal.

PRI originally supplied the US Navy at NSWC Crane with the round forearm free floating handguard for the SPR rifle, which became the Mk12 Mod 0.  This is a recreation of the original rifle, with parts from PRI, Douglas Barrels and other mil-spec providers. Crane had originally produced the Mk12 upper receivers from commercial parts providers, like Precision Reflex.  At the beginning of the War on Terror, when M4 parts were in short supply for regular ground forces, Crane was forced to take out of mothballs M16 A1 lower receivers to mate to the custom uppers that Crane built. Later versions of the Mk12 were found with lower receivers from Colt, Armalite, LMT and regular issue M4.

This Mark 12 Mod 0 is built with PRI's Retro Gen II, which is most representative of the early Mk12 upper receiver groups. Originally, all Mk12s were black, but many found their way to be painted (rattle caned) or Cerakoted FDE. This reproduction is a great addition, and the FDE Cerakoting is done very nicely, and will match most any black or FDE / Tan / Taupe M4 lower receiver.

This upper comes tested by PRI and ready to shoot 5.56mm NATO ammo. Charlie's recommends 77 grain Black Hills or Federal. The upper is equipped with a 18" Douglas 416 stainless steel barrel with a fitted bolt and commercial carrier, flat-top receiver, PRI flip up front gas block front sight with thumb screw elevation adjustment and PRI rear sight, rifle length gas tube, a Gas Buster charging handle with big latch. AE Inc. brake and collar are standard, and profiled correctly to accept the Allen Engineering AEM-5 / Ops Inc. #12 suppressorThe system also comes with a Gen II Rifle length carbon fiber free float forearm and a full length Picatinny top rail.  

This listing is for the 1:7 twist; however, we do also carry the PRI Mk12 Mod 0 SPR FDE in a 1:8 twist (when available).  Precision Reflex provides this reproduction with nice mix of period correct parts, PRI branded parts, and commercially available mil-spec parts to offer the history buff or shooting enthusiast with a good balance between authenticity, performance and price.

We try to keep these uppers in stock; however, demand often exceeds supply. When we are out of stock, and waiting for resupply from PRI, we offer our customers the option to put down a $250 deposit to reserve an upper from the next batch to arrive. If you place a deposit, we will invoice you for the remainder of the purchase price prior to shipping your upper. 


Caliber 5.56/.223
Upper Receiver PRI branded logo / mil-spc forged T6 7075 with hard coat anodizing
Barrel 18"  5.56 NATO chamber Douglas 416 stainless 1:7 twist, branded PRI
Gas Block PRI flip-up front sight gas block with two cross bolts
Forearm PRI Gen2 rifle length round tube with Picatinny top rail
BUIS PRI rear flip-up sight
Muzzle Device Allen Engineering / Ops Inc. brake and collar to fit AEM-5 and #12 suppressor.
Bolt Carrier Group mil-spec phosphated BCG with Carpenter Steel bolt
Top Rail Swan Rail made by PRI
Charging Handle PRI M84 Gas Buster 
Length & Weight 27" / 5-1/4 pounds


Accuracy is based on barrel type 5.56 Douglas sub MOA

Standard on all PRI rifles and uppers are the Gas Buster Charging Handle with Military latch.