98Z5V Posted May 21, 2019 Report Share Posted May 21, 2019 (edited) Check out the video. He brings up some very, very interesting comments, changes throughout the fielding of the rifle. Very good vid on the Mk12. We have stretched my two 5.56 Mk12s to 850 yards at shoots before, and we'll do it again. For 5.56, I love my Mod 0... it's the best. But I think I love my Mod 1 more... 🤩 EDIT - The Mod H, in 6.5 Grendel, is gonna be a completely different animal, and will overtake the other two, by far... I'm just sayin'... Edited May 21, 2019 by 98Z5V Quote Link to comment Share on other sites More sharing options...
Belt Fed Posted May 21, 2019 Report Share Posted May 21, 2019 Nice rifle, I like it. this gonna be your 4th or 5th Grendel. think I read you have four. Quote Link to comment Share on other sites More sharing options...
98Z5V Posted May 22, 2019 Author Report Share Posted May 22, 2019 14 hours ago, Belt Fed said: Nice rifle, I like it. this gonna be your 4th or 5th Grendel. think I read you have four. There are 5 Grendels. Both the Mk12 Mod 0 and Mk12 Mod 1 are 5.56 guns, though. The Mk12 Mod H is a Grendel. There's an M4 Grendel, 18" SPR-barreled SPR-ish Grendel (it's Mk12-ish in it's nature), a light(er) weight 18" Grendel, and the 12.5" Grendel. The Mod H is quite a ways from being finished (need more specific parts), but it fires, and is accurate as all hell. It's gonna be some time before that Mod H is done-done. Quote Link to comment Share on other sites More sharing options...
98Z5V Posted January 16, 2020 Author Report Share Posted January 16, 2020 Very badass article on the Mk12 from Monty LeClair. Very read-worthy, with a ton of great links in the article - it'll send you down that rabbit-hole, I'm warning you now... https://www.arbuildjunkie.com/mk12-spr-navy-seal-monty-leclair/ Here's another one - linked from that article ^^^ https://www.officialjackcarr.com/mk11-12-an-urban-snipers-best-friend/ Might as well just bust it all out... Here are the vid links from that article... ^^^ For the record, on the comments on that one - Vickers states, "Now Monty, you've got an interesting point, as far as you know the Navy never used any of the Mod 0 guns..." Monty states, "That's true, I've never seen any of the Mod 0 guns,... /clip/ ...the only ones I've seen in the inventory are the Mod 1s" Completely true Navy-wise, but that's not what Army did. US Army Special Forces started the Mod 0, and used them (5th Special Forces Group developed the weapon, from it's conception - as well as the "Mod-H", or the Mod-Holland, the 16" variant). 5th Special Forces Group started the entire concept, from soup-to-nuts, and got it rolling in the first place. US Army Special Forces use the Mod 0 - US Army Rangers use the Mod 1, and not the Mod 0. 5th SFG(A) further refined the gun to the 16" barrel, and that was the Mod-H. PRI (Precision Reflex) did all the mods of those gun to the Mod-H - PRI converted them. PRI built most of those Mod 0 guns in the first place, even though NSWC Crane was the proponent for the platform. Crane didn't assemble them - PRI did. PRI 100% did all the conversions from Mod 0 to Mod H, on all those guns. Just a piece of history. Just for the record... Quote Link to comment Share on other sites More sharing options...
98Z5V Posted January 16, 2020 Author Report Share Posted January 16, 2020 More on this, and entirely my own opinion, 100% and then some. The Mk12 was entirely designed around a certain load, a certain projectile, and a certain distance-to-hit ratio. Again, all my opinion - the Mk12 is the most perfect AR15-type gun ever developed. Nothing else in 5.56 will ever beat it - unless you come in here with some F-Class benchrest junk against it. Never has a better combat weapon ever been refined - the Mk12 is the pinnacle of 5.56 refinement. Quote Link to comment Share on other sites More sharing options...
RedRiverII Posted January 16, 2020 Report Share Posted January 16, 2020 (edited) Where can a lesser knowledgeable person find the differences in these platforms? Mod 0, Mod 1, MK12 H etc. Any tables listing the parts? They all seem so similar, my eyes aren't trained well enough to pick out the differences. Edited January 16, 2020 by RedRiverII sp. Quote Link to comment Share on other sites More sharing options...
blue109 Posted January 16, 2020 Report Share Posted January 16, 2020 As much as I hate this place.... https://www.ar15.com/forums/ar-15/-/118-520524/? Quote Link to comment Share on other sites More sharing options...
blue109 Posted January 16, 2020 Report Share Posted January 16, 2020 (edited) Mk12: A BRIEF HISTORY (as authored by "LGT" & "FL") Mk12 Special Purpose Rifle (SPR) Scoped versions of the M16 rifle existed as far back as the 1960s. Like nearly all historic military rifles, the M16 went through decades of efforts to improve its accuracy, both in the military and civilian marksmanship communities. The need for the SPR dates back to the late 1980s and early 1990s when the 7.62mm M21 sniper rifle, a semi-automatic weapon of Vietnam vintage, was replaced by the M24 sniper rifle, a bolt action weapon. The M24 was originally specified to be a .300 Winchester Magnum, but the Army decided to field it in 7.62 NATO for a variety of economic reasons. This left the M24 in the unenviable position of being the worst of both worlds in the eyes of snipers at the time, since it lost the fast-shooing, semiautomatic capability of the M21, but did not gain the range advantage of the .300WM. This compromise left a vacant requirement for a fast-shooting semi-automatic sniper rifle. This need was most apparent in the US Army Special Forces (SF) community, since the other commands within the Special Operations Forces structure filled that need with Knights Armament Corporation's SR-25 sniper rifle. Army SF, being prohibited by its leadership from procuring the SR-25, sought the next best alternative, namely a Special Purpose Receiver (SPR) kit to convert the Army SF M4 carbines into highly accurate rifles. In late 1998, at the request of SFC Steve Holland of 5th Special Forces Group, and the approval of the SOPMOD joint IPT, the Special Operations Peculiar Modifications (SOPMOD) Program Manager, Troy Smith, authorized the purchase of 5 sets of commercial items as an SPR experiment. The original requirement was for USASOC, mainly the SF Groups, as WARCOM had the MK11, 7.62mm system. Once the SPR requirement was developed and demonstrated through experimentation, most of the other commands in USSOCOM added themselves to the Basis of Issue Plan (BOIP). The USSOCOM requirement for the SPR, with improved ammunition, was approved in July 1999, as part of the SOPMOD Kit, Operational Requirements Document, Version 5 (ORD 5). Further initial development included several variants of the SPR and new ammunition that were compatible with the M4 carbine's lower receiver. It was found that standard issue M855 5.56mm ammunition was not consistent enough to meet the requirement. In 2000, based on an upgrade requirement to provide a match-grade trigger to the design, Mr. Paul Miller, the SPR project manager, discovered an opportunity to pick through over 15,000 M16A1s that had been sent to Crane for destruction. Realizing that these M16A1 rifles, some of which were virtually new, could be used as "free lumber” to build full SPR weapons, Paul selected several thousand rifles to be set aside for the new SPR project. The SPR underwent a minor but significant name change, with the R having originally stood for "Receiver” now standing for "Rifle" The new weapon system was worthless without a matching round of ammunition to obtain the performance required. The PEO-SP USSOCOM authorized the new round that became Mk262 as part of the Mk12 system in August 2000. Paul Miller and his SPR team refined the 77-grain prototype ammunition and built approximately 124 SPR Rifles in the summer of 2001. These were finished just in time to ship out to Army SF in late October 2001, to be used in the first invasion of Afghanistan. The SPR rifles were extremely well-received, and the SOF combat units ordered hundreds more. In May 2002, USSOCOM removed the Mk12 and other complete weapons projects from the SOPMOD Program and placed them under the newly-formed USSOCOM Weapons Program. The fielded weapons included two versions (Mk12 Special Purpose Rifle Mod0 and Mod1). Fielding has since been structured for Mk12 Mod1 Special Purpose Rifle only. This rifle is used by Joint USSOCOM Commands and the USMC in combination with M262 (AA53, 77 grain) ammunition. Formal fielding of the full-rate production version of the Mk12 rifle and ammunition occurred in May 2003 and was completed in FY '04. In 2012, as the decade of war on terrorism was winding down and the SCAR weapon system began replacing the requirement for the Mk12, USSOCOM and Naval Special Warfare divested themselves of the Mk12 weapons system, and the Mk12 is now being looked at to fill a Designated Marksman Role within Brown Water Navy commands. Edited January 16, 2020 by blue109 Quote Link to comment Share on other sites More sharing options...
RedRiverII Posted January 16, 2020 Report Share Posted January 16, 2020 Very cool brother, thank you @blue109 Quote Link to comment Share on other sites More sharing options...
blue109 Posted January 16, 2020 Report Share Posted January 16, 2020 There are some guys in there spending huge amounts of time and money to make 100% accurate clone rifles. Not my thing but I respect the dedication. There are some facebook groups and subredits on the subject but that forum is about as good as it gets. Quote Link to comment Share on other sites More sharing options...
RedRiverII Posted January 16, 2020 Report Share Posted January 16, 2020 I just read this and wondered, what if they just decided to buy the 300wm ammo and got on with it, how much money would have been saved? It looks like "for want of a nail he lost his horse." Quote Link to comment Share on other sites More sharing options...
RedRiverII Posted January 16, 2020 Report Share Posted January 16, 2020 Some of us have seen wasted funds, train cars full. You can't buy some decent rounds. Well I see this discussion is bringing me back 50 effin' years in time. Tiger stripes in the States, none in the jungle. ( A buddies gripe not mine ) My poop is still classified but seeing as I do not fathom how much money is actually available, I'm not bitchin', just sayin'. Quote Link to comment Share on other sites More sharing options...
RedRiverII Posted January 16, 2020 Report Share Posted January 16, 2020 "Mk12 Mod0 Build Specifications Barrel: 18-inch match-grade stainless free-float heavy profile with 1:7 ratio, rifle-length gas system Gas Block: PRI flip-up front sight Muzzle Device: OPS Inc. 12th Model muzzle brake / collar to be paired with the 12th Model suppressor Handguard: PRI Gen III free-float Sights: ARMS #40 rear flip-up, PRI front flip-up Optics: Operator-specific but Leupold 3–9×36mm TS-30 A2 and Nightforce 2.5-10x24 NXS are common Buttstock: Operator-specific but A1, A2, and LMT SOPMODs are common Mounts: ARMS #38 SWAN Sleeve rail mount, ARMS #22 medium scope rings, ARMS #32 bi-pod mount (Harris) or ARMS #42 (Versa-Pod) Bi-pod: Harris or Versa-Pod Mk12 Mod1 Build Specifications Barrel: 18-inch match-grade stainless free-float heavy profile with 1:7 ratio, rifle-length gas system Gas Block: Badger Ordnance stainless Mk12 low-profile Muzzle Device: OPS Inc. 12th Model muzzle brake / collar to be paired with the 12th Model suppressor Handguard: KAC M4 Match free-float Rail Adapter System Sights: KAC 600m rear flip-up, KAC front flip-up Optics: Operator-specific but Leupold 3–9×36mm TS-30 A2 and Nightforce 2.5-10x24 NXS are common Buttstock: Operator-specific but A1, A2, and LMT SOPMODs are common Mounts: ARMS #22 high scope rings, ARMS #32 bi-pod mount (Harris) or ARMS #42 (Versa-Pod) Bi-pod: Harris or Versa-Pod Now that we have a little direction here, let's pick up where we left off on all things Mk12..." Looked at the PRI Flip up front site, it's a piece of work Quote Link to comment Share on other sites More sharing options...
Sisco Posted January 16, 2020 Report Share Posted January 16, 2020 (edited) Closest I will ever get to one are the mods I did on my pre Ban Colt AR 15 HBAR match. Replaced the carry handle receiver with a Windham flat top, but reinstalled the 20” chrome lined 1 in 7” barrel. Added a 1x6 Mil Dot scope. Added a Timney single stage trigger, as the Colt Large Pin Geissele type were just too cost prohibitive. Finally spent time two summers ago developing a weapon specific load for Hornady 75 gr BTHP and Lake City brass for the rifle. Entirely satisfied with the result. But have not had the opportunity to shoot it past 200 yards, where it routinely obliterates the “X” ring. the next Mod will be a free float key mod hand guard, though I don’t know if that is really necessary. I don’t know if I can shoot it any more accurately then it does already, considering human(me) error. Edited January 16, 2020 by Sisco Quote Link to comment Share on other sites More sharing options...
Radioactive Posted January 16, 2020 Report Share Posted January 16, 2020 For a mere 2 grand you can get one from centurion hmmmm.... I got more than that in my 260 build. maybe the wife won’t notice if one follows me home or I scrounge up the parts one at a time Quote Link to comment Share on other sites More sharing options...
Radioactive Posted January 17, 2020 Report Share Posted January 17, 2020 10 hours ago, Sisco said: Closest I will ever get to one are the mods I did on my pre Ban Colt AR 15 HBAR match. Replaced the carry handle receiver with a Windham flat top, but reinstalled the 20” chrome lined 1 in 7” barrel. Added a 1x6 Mil Dot scope. Added a Timney single stage trigger, as the Colt Large Pin Geissele type were just too cost prohibitive. Finally spent time two summers ago developing a weapon specific load for Hornady 75 gr BTHP and Lake City brass for the rifle. Entirely satisfied with the result. But have not had the opportunity to shoot it past 200 yards, where it routinely obliterates the “X” ring. the next Mod will be a free float key mod hand guard, though I don’t know if that is really necessary. I don’t know if I can shoot it any more accurately then it does already, considering human(me) error. Got pics? Quote Link to comment Share on other sites More sharing options...
Sisco Posted January 17, 2020 Report Share Posted January 17, 2020 5 minutes ago, Radioactive said: Got pics? Take me a while to dig them out. Had two computers fry recently. Quote Link to comment Share on other sites More sharing options...
Sisco Posted January 17, 2020 Report Share Posted January 17, 2020 (edited) Bad pic HBAR IS at the bottom, AR10T carbine middle M1A on top Edited January 17, 2020 by Sisco Quote Link to comment Share on other sites More sharing options...
Radioactive Posted January 17, 2020 Report Share Posted January 17, 2020 On 5/21/2019 at 1:36 AM, 98Z5V said: Check out the video. He brings up some very, very interesting comments, changes throughout the fielding of the rifle. Very good vid on the Mk12. I like his vids Quote Link to comment Share on other sites More sharing options...
Radioactive Posted January 17, 2020 Report Share Posted January 17, 2020 38 minutes ago, Sisco said: Bad pic HBAR IS at the bottom, AR10T carbine middle M1A on top I like it Quote Link to comment Share on other sites More sharing options...
Sisco Posted January 17, 2020 Report Share Posted January 17, 2020 Total cost,$899 for rifle in 1992, $289 for scope, $135 for Windham upper reciever, $130 for Timney trigger. Total, $1,353. Quote Link to comment Share on other sites More sharing options...
98Z5V Posted January 17, 2020 Author Report Share Posted January 17, 2020 (edited) 17 hours ago, RedRiverII said: Looked at the PRI Flip up front site, it's a piece of work It indeed is. Work of Art, and Function. Sharp eyes will catch something very specific in the pics of this front sight here... I'm with @blue109 on this. I'll never, ever use any Dick Swan parts, ever. There are people that go crazy using exact this-and-that, and I respect that. I'll never do it. I'll use correct major components, but I'll always default to my own personal preferences on a gun, too. Mk12 Mod 0 needs to be running the PRI handguard. Check. It also spec's a specific top rail - that I'll never use - but I'll use the PRI top rail, all day long. IMHO, I don't want to build a 100% period-correct weapon - I want the performance of that weapons platform. Another example - Mod 1s used the KAC rail. Yeah, I get it - I'd rather have the LaRue rail on there, and still make the gun function, as it was functionally designed. I'll stick to the principle of the gun - not the specific choice in it's original parts list. My Mk12 Mod 0 top, Mk12 Mod 1 middle, Mk12 Mod H bottom: The Mod H is a 6.5 Grendel, and it smokes the other two. Badly. Edited January 17, 2020 by 98Z5V Quote Link to comment Share on other sites More sharing options...
98Z5V Posted January 17, 2020 Author Report Share Posted January 17, 2020 ^^^ That Mod H above is still a work in progress. It'll get finished, one day. Mk12s dominated the day for the High Angle portion at the last Fall Shoot. Quote Link to comment Share on other sites More sharing options...
98Z5V Posted January 17, 2020 Author Report Share Posted January 17, 2020 If anyone wants to build a Mk12, the heart of the entire system is the barrel, and you need a very good one. Don't waste the money on uber-expensive barrels, custom-this-and-that - just get a Ballistic Advantage Mk12 barrel - their SPR barrel. I have 4 of them now, Mod 1 is a 5.56 BA 18" SPR barrel, Heavy Grendel is a 6.5G BA 18" SPR barrel, Mod H is the 16" BA SPR Mod H barrel, and the .224 Valk is the 18" BA SPR barrel. @Matt.Cross Mk 12 Mod 1 is the 6.5 Grendel 18" BA SPR barrel. These things WORK, and they don't break the bank, compared to some other "Mk12 specialty barrels." Every one of mine is well under a 1MOA barrel, all day long. My Mod 0 is a Nordic Components 18" precision barrel, that was made by Wilson Arms (not Wilson Combat - different company). Here are the BA barrels that you'd need for one of these builds: 18" .223 Wylde SPR (Mk12 Mod 0 and Mod 1): https://www.ballisticadvantage.com/18-inch-223-wylde-spr-rifle-length-ss-premium-barrel-ops12.html 16: .223 Wylde Mod H SPR: https://www.ballisticadvantage.com/16-inch-223-wylde-spr-mid-length-ss-premium-barrel.html BA now offers them in black nitride now, as well: https://www.ballisticadvantage.com/ar15-barrels/premium-series/223-wylde-premium-black-series Here's the .224 Valkyrie in 18" SPR profile: https://www.ballisticadvantage.com/18-inch-224-valkyrie-spr-rifle-length-ss-premium-barrel.html Here's the Grendel in both 18" and 16" SPR profiles: https://www.ballisticadvantage.com/18-inch-65-grendel-spr-rifle-ss-premium-barrel.html https://www.ballisticadvantage.com/16-inch-65-grendel-spr-mid-ss-premium-barrel.html There is no reason to look at any other barrel manufacturer, if you want to build your own Mk12. There really isn't. You'll spend alot more money on something that won't really give you a giant benefit over a BA barrel - or you'll save alot more money on a shiit-barrel from someone selling cheap barrels, and it won't shoot anywhere close to the BA barrels. Quote Link to comment Share on other sites More sharing options...
98Z5V Posted January 17, 2020 Author Report Share Posted January 17, 2020 (edited) Precision Reflex (PRI) sells complete Mk12 Mod 0 (Gen III or Gen II) and Mod H rifles - you just need to pick your optic and mount, and get it on. https://www.precisionreflex.com/rifle_packages_pr-8619.aspx Edited January 17, 2020 by 98Z5V Quote Link to comment Share on other sites More sharing options...
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