User Panel
Posted: 12/20/2010 8:59:25 AM EDT
[Last Edit: RTUtah]
Originally Posted By PSYWAR1-0:
The Recce platform was something that sprung up within the NSW and 5th SFG communities that first became the Special Purpose Receiver built by Crane, which was supposed to be installed on any M4 lower. After a time when the perfect storm of the users wanting a match-grade trigger and the bolt-bounce issue was identified, the Special Purpose Receiver morphed into a complete rifle that was type-classified as the Mk12. 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. View Quote The following parts lists and substitution parts was compiled by lancecriminal86 over the course of a LOT of research. Read up and pay attention! Below are the 100% .mil-spec parts lists to build a true SPR or Mk12 clone. Some of these parts are no longer manufactured and will require much effort and money to locate through forums and online brokers. Keep in mind the rifles were built off donor M16A1s, hence the prevalent A1 parts in the lower receivers and the BCGs. They were also first configured using parts available from 1998-2004, and most are inferior in some ways to newer designs. If this bothers you too much, STOP NOW. The rifles were issued as a kit in a Pelican 1700 case with cutouts. The kits included the rifle with suppressor, optic, bipod, an Eagle TAS-1 UMSS sling (unobtanium and also absolute crap), with a Dewey 1-piece cleaning rod plus Otis cleaning kit, and a cutout for magazines. An operator's manual was also included, however these have not been officially released for public consumption. However, the manuals are out there, and some companies building Mk12 uppers include one. Whether these are official .mil operator's manuals or specially made is currently unclear as the manual itself still contains language that it is not for distribution. - Alternate .mil-spec parts due to NFA, NLA parts, or changes in name/markings for current production in [brackets] - Extra notes about parts or availability are in (parenthesis) LOWER Lower receivers were standard across the SPR/Mk12 variants and the only variations would be between grips, stocks, and buffers. Most were marked either Colt or GM Hydramatic. All other parts were the same in regards to the lower parts. One caveat is the trigger, as the program originally selected the Knight's Armament 2-stage Full Auto Match trigger. Later on, some issues regarding negligent discharges occurred, and Geissele SSF triggers ultimately found their way into the Mk12 family. Whether 100% of all Mk12s eventually received the Geissele trigger isn't clear, so either is acceptable.
The upper receivers, which ultimately differentiate the four variants of the Mk12, have the most variation between each other. Early SPR/Mod0
ModH, Mod "Holland"
Naturally, once these rifles were issued to units, operators and even Marines used various non-issued parts. Here is a short summary of what has been seen: Early SPR/Mod0: Both Leupold 3.5-10x40mm and 3-9x36mm scopes have been used. Many have had carbine stocks like the old CAR-style, enhanced M4, SOPMOD Gen I, or even the Tactical DuoStock swapped on. Mod1: One 3rd SFG-issued rifle pictured with SSgt Robert J. Miller (MoH recipient) used an A.R.M.S #36 S-EX 5.56mm rail, and a Leupold M3X 10x fixed-power scope, possibly pulled from an M-24 or SR-25 rifle. Another has been seen with a Magpul PRS, LaRue mount, and a Premier Reticles 3-15x used by an AMU shooter, and a similar rifle was pictured on a FOB in a very posed-looking photo. Further, a USMC-issued Mod1 was seen using #22 Medium rings instead of High rings, and a LaRue mount has been spotted as well. Grips have varied from the usual A1, A2, and ERGO, and at least one Magpul MIAD has been used. As with the Mod0s, carbine stocks like the SOPMOD and M4 have been used on Mod1s. ModH: The Mod "Holland" was already a small-batch configuration, but even as soon as they were issued to 5th SFG units, some Ace SOCOM stocks were replaced with Magpul ACS and CTR stocks. Optics are basically anything existing in the unit's inventory, from S&B ShortDots still in the system, the 3-9x and 3.5-10x Leupold scopes from earlier Mod0s, and there's even a photo of an ELCAN on a Mod1 floating around. No non-magnified optics like EOTechs or regular Aimpoint M2/M4s, but Micros have been seen on offset mounts. Backup iron sights, as a whole, were almost entirely left unmounted. Grips were again the same usual selection. Parts Alternatives for Clone Building Many parts are rare, expensive, and/or both. Despite this, there are some alternatives to a 100% pure clone that will still provide the same visual look and performance. While not a museum-grade clone, most would be hard-pressed to discern the difference. Just know there are those of us out there that will haze and peer-pressure you into further moving your build towards a true clone. Barrel: Popular options are the White Oak Armament SPR barrel (rifle gas), BCM's SPR barrel, Rainier's Match and Ultramatch offerings (ensure it's the SPR contour with 12th Model profile), Ballistic Advantage's SPR barrel. Compass Lake Engineering can also spin a Mk12 profiled barrel with a Criterion chrome-lined blank, or even a Krieger, which was one of the original contenders for the program. The DPMS Mk12 barrels are NOT properly profiled for a clone. Optics & Rings: In the case of the Leupold 3-9x or 3.5-10x, it's generally okay to go for a non-illuminated version of either, sometimes with M1 or other turrets and reticles. As far as the NightForce scope, the 2.5-10x24mm is not generally released to the public anymore (with one recent exception through Sniper's Hide), so many use the 32mm or even 42mm versions with the #22 High rings. As for the rings, any of the recent produced A.R.M.S. #22s with the lever-stop humps are functionally the same, the desire for non-lever-stops is purely aesthetic when going for the most authentic look. As LaRue LT-104s have been seen in use, it is justifiable to use one depending on whether you have a specific rifle you want to copy, or even just if you absolutely cannot acquire #22 High rings. A.R.M.S. #38 SWAN Sleeve: The #38 family of sleeves are no longer available. Finding them secondhand usually cost $250-$300 easy, more for rarer early variants. Fortunately, PRi's copies of the sleeves look and function almost identically, with minor visual differences. PRi and other builders supply these currently for complete Mod0 builds. FSB: While the set-screw version of PRi's FSB is spec, most use the cross-bolt, clamp-style version. They are extremely robust, and when aligned and torqued, have been shown to hold strong enough that you'll probably shear your barrel extension pin or upper before it budges. This is mainly how Mod0 uppers are supplied by most vendors, including PRi themselves. Suppressor, Brake/Collar: Diverging from the OPS Inc. or AEM brake and collar will get you MAJOR flak. Trust me, I've been running an AAC SPR/M4 for years now and it took a LONG time to not get clubbed every time I posted it. The Allen Engineering AEM5 is basically the current production of the OPS Inc. 12th Model, as they were originally made by Ron Allen and his team in the first place. Only minor differences separate original OPS Inc. cans from AE cans, and these are only obvious to trained eyes. As far as the rest, you can swap Colt parts out for any other .mil-spec parts, like BCM, DD, CMT, etc. Any billet uppers/lowers, funky BCG coatings, extended bolt releases, etc. are extremely frowned upon. Remember, once you start going down the path of building a "better" rifle rather than what was spec, you're quickly beyond clone territory and would have been better off building a custom 16" or 20" rifle. Cloning is generally viewed as all-in or not at all. * * * * * * * * * * Complete Mk12 Mod0 / Mod1 Uppers Bravo Company Manufacturing High Caliber Sales Precision Reflex Inc. Specific Mk12 Tech Augee's side-by-side comparison of the original ARMS SWAN Sleeve and PRI reproduction PEQ Sleeves: bottom of p136 KOBK's side-by-side comparison of PRI Gen I, II, and III handguards, and Gen I and Gen II FSBs, and SWANs: middle of p137 Augee's Mod1 gas block tech: top half of p357 Glass1's Early Mod0 photo breakdown: middle of p449 tamboi's Leupold Vari-X, TS30, and TS30A2 scope history/lineage, and part numbers, p.792 Attached File |
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MACV-SOG nut.
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Off the record, I love your new bangs, Mrs. Obama
OR, USA
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Originally Posted By SDMF_Rebel:
It shouldn't, but if the can is the only variable, gas is your answer. I'm so over gassed with an h2 that I stack brass damn near in front of the muzzle. Never chokes. View Quote View All Quotes View All Quotes Originally Posted By SDMF_Rebel:
Originally Posted By TigerHawk:
My dealer did a range day yesterday and I got a chance to try out my aem5. I was super excited about how quite the thing is, grinning ear to ear. I was having a failure to feed problem though.. only had a heavy buffer and standard spring with me. Would something a little heavier help correct this? Maybe a H2 with a stiffer spring? I’m guessing it’s a little over gassed with the suppressor. http://i.imgur.com/QAwogOQ.jpg I'm so over gassed with an h2 that I stack brass damn near in front of the muzzle. Never chokes. |
"The only thing more boring than shooting groups is looking at other people's groups on the internet." -erud
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Originally Posted By kells81:
Mail call from Leupold. I asked for one marked Mk12 Mod 1 but it came as being marked SPR. Either way one of them will work on my Mod 0. https://www.AR15.Com/media/mediaFiles/43495/63C215DB-6158-4920-8310-83FA5D4BB055-683602.jpg View Quote |
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You could use a crush washer or stack some copper washers from an oil pan drain plug on a car...Ive seen both done and they work fine.
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Strength Determination Merciless Forever
PA, USA
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Just shim out the brake.
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I'd go peel washer, maybe add a thick shim if needed. Ron Allen has noted that most crush washers aren't crushing evenly, so he's including shims and crush washer now.
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Got my $50 SOCOM installed. Makin progress. Still need LT-104, Gasbuster, and 8" bottom rail.
Holland Progress Late Sep 2018 by Armed Ferret, on Flickr |
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So I would use shims and a crush washer? Or can I just shim it like a surefire muzzle device?
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Originally Posted By ArmedFerret:
Got my $50 SOCOM installed. Makin progress. Still need LT-104, Gasbuster, and 8" bottom rail. https://farm2.staticflickr.com/1933/30037711777_549191a932_c.jpg Holland Progress Late Sep 2018 by Armed Ferret, on Flickr View Quote While not Gen 1 correct, I won’t feel bad rough handling it if the need arises. |
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Originally Posted By ArmedFerret:
Got my $50 SOCOM installed. Makin progress. Still need LT-104, Gasbuster, and 8" bottom rail. https://farm2.staticflickr.com/1933/30037711777_549191a932_c.jpg Holland Progress Late Sep 2018 by Armed Ferret, on Flickr View Quote |
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Without blood, it doesn't count!
"A gun, like any other source of power, is a force for good or evil, being neither in itself, but dependent upon those who possess it." |
Without blood, it doesn't count!
"A gun, like any other source of power, is a force for good or evil, being neither in itself, but dependent upon those who possess it." |
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Originally Posted By ArmedFerret:
A shooting buddy who also happens to be my civilian doc. It was "too heavy" for him so I scored. View Quote View All Quotes View All Quotes |
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Without blood, it doesn't count!
"A gun, like any other source of power, is a force for good or evil, being neither in itself, but dependent upon those who possess it." |
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theyve probably been posted in the thread a few times but does anyone have any pics of the mk12 mod 1 "in the wild"?
skipping around to random pages has found me a couple. |
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Originally Posted By SurtrsFire:
theyve probably been posted in the thread a few times but does anyone have any pics of the mk12 mod 1 "in the wild"? skipping around to random pages has found me a couple. View Quote |
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PSALMS 144-1
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Originally Posted By Regulatori:
I believe you want more than that. Like 7-11 is optimal. View Quote View All Quotes View All Quotes Originally Posted By Regulatori:
Originally Posted By TigerHawk:
It fed very reliably without the suppressor so hopefully I can tune it with just buffer weight/spring. Is 5 full turns within spec for mounting the can? Is the spec for AEM cans any different? Instalation with the crush washer and KAC shims to give initial tightness at 10 to 10:30 tightened to 12:00. |
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Originally Posted By prskiller:
https://i.imgur.com/7MoLQj7.jpg https://i.imgur.com/hMUcetU.jpg https://i.imgur.com/mGOllRd.jpg https://i.imgur.com/XUxydof.jpg View Quote View All Quotes View All Quotes Originally Posted By prskiller:
Originally Posted By SurtrsFire:
theyve probably been posted in the thread a few times but does anyone have any pics of the mk12 mod 1 "in the wild"? skipping around to random pages has found me a couple. https://i.imgur.com/hMUcetU.jpg https://i.imgur.com/mGOllRd.jpg https://i.imgur.com/XUxydof.jpg |
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Without blood, it doesn't count!
"A gun, like any other source of power, is a force for good or evil, being neither in itself, but dependent upon those who possess it." |
PSALMS 144-1
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"When a man knows he is to be hanged in a fortnight, it concentrates his mind wonderfully." - Dr. Samuel Johnson
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Originally Posted By ArmedFerret:
Be a while before mine is done and i wont be using a ts30 but I'll tape the fuck outta my stock....i have like 6 rolls of that shit left over. View Quote View All Quotes View All Quotes |
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Without blood, it doesn't count!
"A gun, like any other source of power, is a force for good or evil, being neither in itself, but dependent upon those who possess it." |
Originally Posted By MrJonesandMe:
Black things get hot as hell when they're in the sun all day. This helps a little at least. View Quote View All Quotes View All Quotes |
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Without blood, it doesn't count!
"A gun, like any other source of power, is a force for good or evil, being neither in itself, but dependent upon those who possess it." |
Off the record, I love your new bangs, Mrs. Obama
OR, USA
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"The only thing more boring than shooting groups is looking at other people's groups on the internet." -erud
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Strength Determination Merciless Forever
PA, USA
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Originally Posted By ankratz:
Boys, get your early SPR builds ready... We may have a color match for FML Tan. https://www.AR15.Com/media/mediaFiles/232334/43034938_10160978672055118_3181655830927769600_o-690133.JPG View Quote |
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Originally Posted By SecretSquirell:
I know this (BTDT and all that jizz), but he's not putting his cheek on the bottom of the stock. View Quote |
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Originally Posted By Ed_Victory:
Still waiting for someone to clone the one with a Duostock. View Quote View All Quotes View All Quotes |
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Originally Posted By ankratz:
Boys, get your early SPR builds ready... We may have a color match for FML Tan. https://www.AR15.Com/media/mediaFiles/232334/43034938_10160978672055118_3181655830927769600_o-690133.JPG View Quote Hope you guys can send the actual color samples out to me, I'll have them photographed alongside the original upper. That should make it pretty easy to determine the closest tan mix. |
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Off the record, I love your new bangs, Mrs. Obama
OR, USA
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Originally Posted By USMCSGT0331:
Those pics of the SPR upper look very familiar...... Hope you guys can send the actual color samples out to me, I'll have them photographed alongside the original upper. That should make it pretty easy to determine the closest tan mix. View Quote View All Quotes View All Quotes Originally Posted By USMCSGT0331:
Originally Posted By ankratz:
Boys, get your early SPR builds ready... We may have a color match for FML Tan. https://www.AR15.Com/media/mediaFiles/232334/43034938_10160978672055118_3181655830927769600_o-690133.JPG Hope you guys can send the actual color samples out to me, I'll have them photographed alongside the original upper. That should make it pretty easy to determine the closest tan mix. |
"The only thing more boring than shooting groups is looking at other people's groups on the internet." -erud
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Off the record, I love your new bangs, Mrs. Obama
OR, USA
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Originally Posted By USMCSGT0331:
Just sent you an email, I'm willing to help out any way I can with this project. View Quote View All Quotes View All Quotes |
"The only thing more boring than shooting groups is looking at other people's groups on the internet." -erud
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Looking at using the Vortex Diamondback Tactical scope. It has a 44mm objective. Will the med 22 rings work? Rifle is a Mod 0.
http://www.vortexoptics.com/product/vortex-diamondback-tactical-4-16x44-FFP-riflescope_with_ebr-2c_mrad-reticle |
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use code CD2018 for 15% off pri stuff at Black phase tactical today through the 8th.
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Originally Posted By Bmurray6999:
Looking at using the Vortex Diamondback Tactical scope. It has a 44mm objective. Will the med 22 rings work? http://www.vortexoptics.com/product/vortex-diamondback-tactical-4-16x44-FFP-riflescope_with_ebr-2c_mrad-reticle View Quote |
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More worried about the objective clearing the rail using the medium height rings
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...
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Originally Posted By Bmurray6999:
Looking at using the Vortex Diamondback Tactical scope. It has a 44mm objective. Will the med 22 rings work? Rifle is a Mod 0. http://www.vortexoptics.com/product/vortex-diamondback-tactical-4-16x44-FFP-riflescope_with_ebr-2c_mrad-reticle View Quote |
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Originally Posted By Bmurray6999:
This is would be temporary until I can get my hands on a clone correct optic. View Quote View All Quotes View All Quotes Originally Posted By Bmurray6999:
Originally Posted By lancecriminal86: This is a clone thread, not going to find much help here fitting Vortex scopes. And I have to ask, why not just keep the money and save a bit longer for a used Leupold? Unless you really want to keep that Vortex for later you're less likely to recoup that cost that you could have just applied to the glass you really needed. Don't focus on the commercial TS30A2s, just look for a 2.5-8 or 3.5-10 with illum reticle and M2 or M3 turrets. They pop up now and then, and for a lot less than some retailers are trying to charge for a scope that isn't even correct. |
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Originally Posted By lancecriminal86:
This seems to show the safety being black: https://i.imgur.com/vhH87at.jpg Looks mostly black, but almost seems like it's worn off perhaps? Looks more like an A2 grip than Ergo https://i.imgur.com/bHFvLYH.jpg View Quote |
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http://www.amazon.com/Gentle-Propositions-J-S-Economos/dp/0615997635
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Originally Posted By lancecriminal86: I had a Bushnell 3-12x44 clear with #22 M rings on a Swan sleeve. And I have to ask, why not just keep the money and save a bit longer for a used Leupold? Unless you really want to keep that Vortex for later you're less likely to recoup that cost that you could have just applied to the glass you really needed. Don't focus on the commercial TS30A2s, just look for a 2.5-8 or 3.5-10 with illum reticle and M2 or M3 turrets. They pop up now and then, and for a lot less than some retailers are trying to charge for a scope that isn't even correct. View Quote |
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Originally Posted By RTUtah:
That safety definitely had the paint worn off, no question about it by my eyes anyways. View Quote View All Quotes View All Quotes Originally Posted By RTUtah:
Originally Posted By lancecriminal86:
This seems to show the safety being black: https://i.imgur.com/vhH87at.jpg Looks mostly black, but almost seems like it's worn off perhaps? Looks more like an A2 grip than Ergo https://i.imgur.com/bHFvLYH.jpg I really do think the Safety, like the ARMS sleeve, ops brake/collar, rings, rear sight, and maybe grip were un-coated. |
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