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Thread: Mk12 SPR Build

  1. #1
    Join Date
    May 2010
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    Minnesota
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    Default Mk12 SPR Build

    I'm in the process of building a Mk12 SPR variant. Here are a couple photos from the build. I'll post up more as I go. Everything is basically set to go, except the barrel. Not a lot installed right now, but working at it. Still waiting on the Mk12 barrel from DPMS.

    Also, you can follow the build (and other builds in progress) on my website, UnaStamusCombat.com:
    http://unastamuscombat.com/concept_weapons.html


    A couple photos from the site:

    Base Platform: DPMS A15 Carbine







    Parts and the build in progress:










    Cheers!

  2. #2
    Join Date
    May 2010
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    Minnesota
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    Default Re: Mk12 SPR Build

    Alright, here's the first SPR mock-up. It'll be set to go once I get the 18" Mk12 barrel in. For now, it just retains the 16" carbine barrel.
    I anticipate the scope coming in sometime within the next week or two. No clue how long it'll be for the barrel.






  3. #3
    Join Date
    Jan 2009
    Location
    Arizona
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    138

    Default Re: Mk12 SPR Build

    What twist is the barrel in it now?

    We've experimented with rifles as short as 12.5" in our courses with excellent results as long as tight twist/heavy bullet.

    This might be the first time in history where short is sexy! ***NOBODY USE THAT, IT JUST POPPED OUT OF MY BRAIN AND WOULD LOOK COOL ON A GPS SNIPER SCHOOL SHORT-BARREL SNIPER RIFLE T-SHIRT!!

  4. #4
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    Jan 2009
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    Arizona
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    Default Re: Mk12 SPR Build

    BTW, great write-up on your website. Feel free to cut and paste it onto the forum. I like the way you broke down each step for everybody to both see and understand. Good job.

  5. #5
    Join Date
    May 2010
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    Minnesota
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    Default Re: Mk12 SPR Build

    Quote Originally Posted by William Graves View Post
    What twist is the barrel in it now?

    We've experimented with rifles as short as 12.5" in our courses with excellent results as long as tight twist/heavy bullet.

    This might be the first time in history where short is sexy! ***NOBODY USE THAT, IT JUST POPPED OUT OF MY BRAIN AND WOULD LOOK COOL ON A GPS SNIPER SCHOOL SHORT-BARREL SNIPER RIFLE T-SHIRT!!
    The barrel is the stock 1:9 DPMS 16" carbine contour. It can barely hold 3MOA on a good day with 55gr loads (XM193 and Hornady Custom both). I don't know how many thousands of rounds I have though it, but it's taken a LOT of abuse. I need to get a barrel on there that I'll actually take care of.
    I DO love the look of it now, though with the 16" barrel. DPMS said the Mk12 barrel was going to take anywhere from 5 weeks to 5 months. I will be calling DPMS this week, as it's been a month since I last harassed them. If I don't hear anything back from DPMS in the near future about my barrel, I'll probably bite the bullet and go to Noveske and get the 16" Recon or 18" SPR barrel. I like Noveske, and the 1:7 improved Polygonal barrels are nice. I hear good things for accuracy.

    I'm also still waiting for my scope. I should have gotten it by now, but I guess I wasn't as high on the Vortex Viper PST list as I thought...


    Question though:
    Would there really be a significant difference between 16" and 18" in terms of exterior and terminal ballistics for an SPR? Or would it still be advisable to stick with 18" just for good measure?



    BTW, great write-up on your website. Feel free to cut and paste it onto the forum. I like the way you broke down each step for everybody to both see and understand. Good job.
    Thanks! I was getting asked on other sites if I liked certain items or why I picked certain things, so I figured that each portion could be a mini write-up/review. The weapons portion of the website was partially designed to be an end-user (patrol officer, SWAT operative, federal agent) reference to help them consider options for equipping themselves and their departments, since often times departments rely on only a few people to decide how to outfit the whole agency. Part of it was also directed at my department, as I'm trying to do some some petitioning and proposals in hopes of implementing DMRs or SPRs.
    We had a 20 minute stand-off last night after a car chase and the guy was non-compliant and kept reaching down into his lap as he stayed seated in the car. I remember thinking that that was a place where an SPR could have been helpful for better surveillance and cover (fortunately County K9 showed up and turned the guy into a chew toy ).


    Also, once my NFA stamp gets here for my PDW rifle, I'll be doing some ballistic gelatin testing with duty .223 loads. I want to definitively see proof of whether or not SBRs affect terminal ballistic performance. I figure a 7.5" barrel would be a good test of that. Once that happens, I'll post the photos of that here too, but all in good time.

  6. #6
    Join Date
    Jun 2010
    Posts
    8

    Default Re: Mk12 SPR Build

    If possible, you could order the Mk12 barrel from a another vender. I noticed that Midwayusa has them in stock for 179.99 with the gas block.

    http://www.midwayusa.com/viewProduct...tNumber=431749

  7. #7
    Join Date
    May 2010
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    Minnesota
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    Default Re: Mk12 SPR Build

    Quote Originally Posted by michael View Post
    If possible, you could order the Mk12 barrel from a another vender. I noticed that Midwayusa has them in stock for 179.99 with the gas block.

    http://www.midwayusa.com/viewProduct...tNumber=431749
    Holy crap they do!! Nice find, thanks!
    I just ordered it and canceled my DPMS direct order.

    Now it's an unknown wait time for the scope...

  8. #8
    Join Date
    May 2010
    Location
    Minnesota
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    Default Re: Mk12 SPR Build

    Well, the Mk12 barrel came in this morning. I've already done a mock-up and now am waiting for the loctite to dry on the Mk12 gas block bottom screws. Once that's done, I'll finalize the build. Barrel is still black, though. I'm most likely going to paint it, but probably not until later tonight. Now I just have to wait for word on the scope, which is still backordered.









    Note the gas block position, and how the gas tube and gas block stay completely protected








    And finally, here's comparison of the barrel contours between the 18" Mk12 (top) and the 16" Carbine (bottom):


  9. #9
    Join Date
    Jul 2009
    Location
    So. Cal
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    Default Re: Mk12 SPR Build

    update!!!

  10. #10
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    May 2010
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    Minnesota
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    Default Re: Mk12 SPR Build

    Yeah, I should probably throw in an update.

    Topped the rifle with a Vortex Viper PST 2.5-10x40 EBR-1 MRAD scope.
    The scope pulled a good group last time out with handloaded 77gr SMKs. I shot a 7 shot group at .807 MOA. I fired a group of 5, saw that I pulled a shot, and then re-engaged with two more rounds to confirm it was my error and not the rifle. Confirmed. The main grouping is a .460 MOA, which is a real reflection of the rifle's accuracy.






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