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Posted: 5/9/2006 8:11:32 AM EDT
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I have decided for some unknown reason I want an SPR. I want it as close to a MK12 Mod 0 as possible but not sure what it all entails. Right now I have a RRA lower and a CMT complete M4 cut upper with no barrel or forend. Thank you in advance for any information. PS all I found was a Wikpedia entry that was confusing as heck |
You'll also need the ARMS rail and QD scope mounts and a Leupold illuminated MRT 3x9 to make it completly accurate to the Mod 0 specs. You'll also need the suppressor OPS Inc makes as well. The barrel is made by Compass Lake. |
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en.wikipedia.org/wiki/United_States_Navy_Mark_12_Mod_X_Special_Purpose_Rifle#Specifications Specifications Upper Receiver: The upper receiver blocks themselves were initially supplied by Colt, with some of those being from Diemaco as well (Colt has been outsourcing parts of its production to the Canadian firm for a while now -- 02/05 Colt has purchased Diemaco, but continues to supply firearms under both names). There is a debate about whether the upper blocks for the Mk 12 rifles, though, came solely from Armalite, or were a mix of receivers from Armalite and Colt/Diemaco. All of these upper receivers were flat top, but have been seen both with the old style tear drop forward assist and the new round style. There is, however, no obvious consistency in this regard. Lower Receiver: When the SPR program was still in the phase where it was just a receiver, Crane assembled all of its protos using either M16A1 or M4A1 lowers. It is unknown whether this pattern continued as the program progressed. There is also some issue about whether, when the Navy type-classified the weapon, Precision Reflex Incorporated (PRI) began assembling the rifles themselves. While a number of options were tried in the end, a KAC 2-stage trigger was finally decided upon as the standard fit. Barrel: A 18 in (457 mm) threaded-muzzle match-grade free floating stainless steel heavy barrel with a 1:7 in (178 mm) rifle twist ratio. The barrels have a special contour to maximize accuracy and minimize weight; they are manufactured by Douglas Barrels. An OPS Inc. muzzle brake and collar (to align the OPS Inc. 12th Model Suppressor) is installed with the barrel. These barrels were designed to take advantage of the new 77 grain (5 g) Mk 262 cartridge that is now being fielded. Buttstock: SPRs in action have been seen with M16A1 buttstocks, M16A2 buttstocks, retractable M4 buttstocks, and the Crane Enhanced retractable buttstock. It is readily compatible with any type of stock system developed for the AR-15 weapon system. Handguards: In all cases a free floating forearm is utilized. This handguard does not ever touch the barrel, increasing the accuracy of the weapon by removing increased vibration exerted on the barrel by the rest of the gun. The first SPRs use a PRI Gen I or Gen II carbon-fiber free-float tubes. The SPR/A, SPR/B, and Mk 12 Mod 1 all use the Knights Armament Company (KAC) M4 Match Free-Floating RAS (Rail Adapter System). The Mk 12 Mod 0 uses PRI Gen III free-float tubes. The Gen I and Gen II Freefloat Forearms are combined with the Atlantic Research Marketing Systems (ARMS) #38 SPR MOD Sleeve, while the Gen III Freefloat Forearm, due its it larger barrel nut, only works with the ARMS #38 SPR PEQ-2-3. Sights: The original SPR used an early PRI flip-up front sight with an elevation dial, which has since been discontinued. The Mk 12 Mod 0 uses the current PRI flip-up front sight. The SPR/A, SPR/B, and Mk 12 Mod 1 use the KAC rail foreend flip-up front sight. The SPR and Mk 12 Mod 0 use the ARMS #40 flip up rear sight. The rest of the models use the KAC 600 meter flip up rear. Optics: Due to the relative modularity of the system, optics (as well as almost everything else) can be mounted per the operator's wishes, however, this weapon system is most often seen with a 3.5–10x40 mm Leupold LR M3 (SPR/A), 2.5–9x36 mm TS-30 (SPR/B), or 3–9x36 mm TS-30 A2 (Mk 12 Mod 0/1) Mid Range/Tactical Illuminated Reticle Dayscope (civilian versions are known as the Leupold Mark 4 MR/T 3–9x36). Night vision devices can also be attached. These scopes usually come with flip open dust covers and a honeycomb anti-glare anti-reflection device (ARD). Mounts: As mentioned before, a long accessory rail, called a SWAN Sleeve (ARMS SPR MOD or ARMS #38 SPR PEQ-2-3), manufactured by ARMS, is installed, running the length of the rifle. The SPR/A and SPR/B both used the KAC M4 Match FF RAS. Two ARMS #22 Throwlever 30 mm steel rings are used to mount the dayscope. The SPR/A, SPR/B, and Mk 12 Mod 1 use ARMS #22 high rings, while due to the increased height from the SWAN Sleeve, the SPR and Mk 12 Mod 1 use ARMS #22 medium rings. An under-the-handguard ARMS #32 Throwlever mount is used to quick release mount the Harris bipod (the ARMS #42 Throwlever mount is used to mount the Versa-Pod.) Bipod: Originally Versa-Pods, a cheaper Chinese-made copy of the relatively expensive Parker-Hale swivel bipod, were used, but were taken off the system after the initial SPR. Currently, a Harris swivel model bipod is typically used with the SPR, and is sometimes seen with a KMW Pod-Loc tension adjustment device. As mentioned above, the bipod is mounted via a ARMS #32 throwlever device attached to the bottom rail of the rifle's forearm. The ARMS mount is used on both Mod 0 and Mod 1. Suppressor: The suppressor threads directly onto the OPS Inc. muzzle brake and uses the collar to stay centered. It is an OPS Inc. 12th Model SPR Muzzle Brake Suppressor (MBS). Ammunition: The SPR is not used to fire standard issue M855 ball or M856 tracer (and even less so M193 ball). Due to the limits in performance and poor accuracy of the 62 grain (4 g) M855 ball (standard NATO green-tip .223), the Mark 262 Open Tip Match (OTM) round was developed as a more accurate 5.56 x 45 mm round. The cartridges are made by Black Hills Ammunition. The first production batches were designated the Mk 262 Mod 0 and used a Sierra Bullets MatchKing 77 grain (5 g) Hollow Point Boat Tail (HPBT) bullet without a cannelure (crimping groove). Black Hills then approached Nosler, who made a similar 77gr OTM bullet, and Nosler agreed to supply cannelured bullets to Black Hills. This load was designated Mk 262 Mod 1. Recently, Sierra agreed to add a minimal crimp to their bullet, and this has since replaced the Nosler bullet in the current versions of Mk 262 Mod 1. |
Mostly - a lot of friggen money!!!  Seriously, if you want a true SPR Mod 0 - "just because" that fine, have at it. Just know that they are really expensive to build to "spec". You can build a SPR type (more along the lines of a Mod1) for a lot less money and have a weapon that is just as accurate and functional. There was a guy here not too long ago who build a whole SPR type weapon (minus BUIS's) for something like $1-1.2K and it was a real tack driver. You would spend that much buying\building a MK12 Mod 0 upper (using all new parts) and then you would still have to buy a complete lower, match trigger and optics. Just some food for thought. |
Very true. I built up my own "true" SPR clone about 2 years ago. Cool looking at it is a true 1/2 MOA rifle. Very $$$$$$$$44 Upgraded my 20in mil spec barreled gun with a WOA SPR Barrel from Adco and a RR two stage trigger. Already had a FF handguard on it. JUST AS ACCURATE AS THE $$$$$$$$$$$$ SPR CLONE. Point being....match barrel, good two stage trigger or light single stage, and free float the barrel. The rest of it is unncessary cosmetics with ltd functional benefit. |
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To help you out, here's the specs on my MK12 MOD0 Clone (with little extras that I put in): UPPER ASSEMBLY: CMT A3 Upper with Feed Ramps WOA 18" SS SPR Bbl, Rifle Gas System w/M4 Cuts (bead blasted/KG guncoat Black) RRA Bolt/Carrier Group RRA Rifle Length Gas Tube PRI Flip Up Front Sight PRI GENIII Free Float Tube with Rails PRI M84 Gas Buster Charging Handle Ops Inc Type Brake & Collar Set Leupold Vari-X III Tactical 40mm Scope w/Mil-Dot; Butler Creek Scope Caps; & 2.5" Hood ARMS PEQ-2-3 Swan Sleeve ARMS #40L BUIS ARMS #32 QD Bipod Mount ARMS #22M Scope Rings ARMS #37 1" Ring Inserts ARMS Tactical Ring Cap (TRC) ARMS Tactical Ring Rail (TRR) Harris 6-9 Swivel Bipod w/Pod-Loc LOWER ASSEMBLY: RRA US Property marked lower w/ RRA internals Jewell 2 Stage Match Trigger KNS Anti-Rotation Trigger/Hammer Pins Magpul Enhanced Trigger Guard Magpul PRS Enidine Rifle Buffer Sierra SPR Grip 20 Rnd Mags It is quite pricey but shoots pretty accurate and is a good conversational piece on the range .
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FYI- Compass Lake is not "authentic" though they are about as close as most can get. Real Mk12 barrels are Douglas SS contured by Gene Barnett. Barnett developed that contour, everyone else is standing on his shoulder. Some people are lucky enough to know the guy and can get authentic ones. Everyone has their method of creating a barrel from a blank, but Barnett takes things a little further than most with some of his post-production steps. When getting your barrel, you do need to make sure you get a true SPR speced barrel. Most of the "SPR" advertised barrels are simply 18" stainless steel and will not be compatible with the OPS Inc barrel collar. CMMG, DPMS, Noveske and others offer "SPR" barrels, but you will find that they are not contoured to true SPR spec and hence will not fit an OPS inc collar correctly. MSTN, Compass Lake and WOA all do true SPR spec barrels, but you need to specify that you want to use the OPS inc collar. Noveske can do them too, he knows the spec, but again, it's a special order. |
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