Mk12 Mod 1 Near Clone Upper Receiver Group, complete from Potomac Armory

$1,648.00 - $2,279.00
assembled as ordered, generally ships within 3 weeks

Mk12 Mod 1 Near Clone Upper Receiver Group, complete from Potomac Armory

featuring 18" SPR barrel and Allen Engineering hardware and your choice of barrel, sights and mount

Lone Survivor Gun

Seen here in Lone Survivor, the Mk12 sniper rifle started as the SPR project in late 1990's and became the most popular M16 / M4 based 5.56 sniper rifle in the global war on terror.  The Mod 1 version got started with NSWC in 2001/2002 and spread from the US Navy SEALS to USMC, and has been one of the more fun guns to build, buy and shoot.  The accuracy of a tuned Mk12 with the right barrel and ammo is very accurate at distances beyond 600 yards.

The Near Clone model takes the best of the military correct upper receiver group and finds ways to go beyond hard to find parts and / or expensive parts and make a good replica available in much the same way that PRI has made a near clone Mk12 Mod0 available to the public.  Potomac Armory has worked with Charlies to design and assemble a very good shooting upper, which can be nicely paired with any solid forged military style lower, like Colt, FN, LMT, Rock River and others.

Mk12 barrel

The heart of a sniper rifle is the barrel, and here, we present the option of either a military clone correct Douglas 18" barrel in 416 stainless steel button cut with a 1:7 twist and chambered in CLE (very similar to 5.56 NATO and .223 Wylde), or a Criterion barrel with the same specifications.  Douglas is the barrel that came with the Mk12, and Criterion is a solid choice of good barrel making at a slightly lower price point.  Your choice might be a matter of what is in stock at the time you order. 

Mk12 handguard / rail

The upper receiver comes with a Midwest Industries T-Series Combat Rail in 12.625" length.  Midwest Industries builds high quality rails and other components and does not charge a premium, but has been known for solid workmanship.  The CRT rail is very similar in look and design to the Knights Armament rail, which is the military correct rail originally found on the Mk12 Mod1.  The KAC RAS was one of the first free-floating rails, which takes the pressure of the bipod, hand and accessories off of the barrel to add to the accuracy of the barrel and the entire weapon system.  Midwest Industries features a more advanced design than existed back in 2001, but the principle is very similar:  offer a four sided 1913 rail platform that is free-floating.  The MI CRT rail adds a built-in QD disconnect at the rear of both sides of the rail.  The 12.625" length presents the Mk12 gas block slightly ahead of the rail and exposed, in the same manner as the KAC RAS does.

The MI CRT rail is accented with Knights style rail covers (made by Prudent American Tech; formerly P&S), to help give you that Mk12 characteristic look.

Upper Receiver

The upper receiver is a military grade forged receiver, of similar quality to many name brand mil spec receivers, but does not have a dry lube interior, for example, like Colt does.  The receiver will come from one of several name brand forges and have the marking of a square, keyhole or broken-A.

Mk12 Gas Block and M68 charging handle

The Potomac Armory Mk12 Mod 1 near clone upper also features the PRI M68 black gas buster charging handle and a NAVSEA Mk12 gas block and military grade stainless gas tube, which were standard on military issue Mk12's.  The PRI Gas Buster M68 charging handle was ahead of its time, and provided a good barrier from the shooter face to the noxious gasses inside the charging area.  The Mk12 gas block has been used by the Navy SEALS for 20 years, and will not come off.  Some recent marketing has touted the advantage of a pinned gas block, but with the correct dimpling of the barrel and Loctite application to the set screws, the gas block is not coming off without some serious gunsmith attention.  Having a true Mk12 gas block is a sign of having the correct components for the rifle of this period.

Ops Inc. Hardware

As the military correct Mod 1 uppers would have, as well as the Allen Engineering SPR long collar and perfectly timed brake with thread protector.  The Allen Engineering hardware is 100% the real deal, as Allen did all the construction of the earlier Ops, Inc. suppressors and hardware.  The installation of the brake is checked by manually attaching a suppressor to assure the correct number of turns to secure an Ops Inc style suppressor.  This is where the craftsmanship comes in:  adding the right number of shims and spacers to assure the proper alignment of the break ports, while also providing for the correct installation of the suppressor.  Every upper is checked for suppressor fit and then bore alignment using a Surefire bore guide.

Sights and Scope Rings

Charlie's knows that some guys buy parts and hold them, and others have their own favorite sights or scope mount, so the sights and rings are offered as an option.  If selected, the back-up iron sights are the military correct Knights flip-up sights:  rear full size 200-600 meter sights and front M4 period correct flip-up sight in black.  The rings, if selected are the ARMS #22 HIGH rings in 30mm, which is perfect for the period correct Leopold or Nightforce scopes, or another scope of your choosing.  Note:  Pictures show the optional back-up iron sights install, but are an option, as is the case with the scope rings.


  • milspec forged upper receiver 7075-T6 military grade aluminum, complete and Type 3 hardcoat black anodizing
  • SPR profiled barrel in 416R stainless with your choice of Douglas or Criterion blanks, handcrafted by Compass Lake Engineering in their CLE chamber, 1:7 twist, 18.1", coated in US Navy spec gray Gunkote.
  • Allen Engineering SPR brake and long collar, professionally timed and installed while attaching an AEM5 suppressor for testing and tested with bore rod for concentricity
  • Midwest Industries CRT quad rail with Picatinny on all four sides
  • Rail is 6061 aluminum for lightweight and Type 3 hardcoat anodized in black, 2.43" tall and an inner diameter of 1.3"
  • 4140 heat treated barrel nut with screws and barrel wrench included
  • Precision Reflex factory M68 Gas Buster charging handle
  • NAVSEA Mk12 gas block, phosphated steel alloy with military grade stainless gas tube, either Colt or Remcon
  • military grade milspec phosphated and chrome lined bolt carrier group with MPI tested bolt in either 158 Carpenter Steel 9310 Steel and 8620 carrier
  • mil-spec (3) 11-ribbed black rail covers - similar to Knights, but made by Prudent American Tech, another military contractor.
  • Optional:  ARMS #22 HIGH 30mm rings
  • Optional:  Knights Armament full sized 600 m rear sight and 99051 black front sight as back-up irons.