308 suddenly not grouping well?

Discussion in 'Big Stuff -- 6.5mm, 7mm, 30 Cal' started by MOA, Jun 30, 2018.

  1. MOA

    MOA

    Joined:
    May 16, 2009
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    So i promised a update. Shot the rifle in a match saturday with no shots fired to see if cleaning with Iosso had fixed the inaccuracy. It was a 100 yard benchrest match(not registered or anything) with unlimited sighters. The first round went 3.5" low and 1" left. Dialed adjustment and second round went in the same hole... Dialed adjustment again and it moved 1" high and 1" right. No adjustment and fired again. Level with bull 1" left. It took 10 sighters for the rifle to calm down, which ultimately brought it back to its original zero. Took another 10 rounds to get the groups where they should be. Posted a vest group of .315(i know, not really a good benchrest score) but enough to win out of our 12 shooters.
    Also placed very well in our groundhog score match with a 248 6x.
    All shooting was done with federal gmm 175. So it seems that hard carbon was the problem, if not a gentle scrub fixed it anyway. Thanks for the help guys.
     
    davidjoe and #40Fan like this.
  2. #40Fan

    #40Fan

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    Thanks for the update.
     
  3. Nature Boy

    Nature Boy

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    Feb 28, 2017
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    Out of curiosity, what bullet are you shooting?

    The reason I ask is my FN SPR got copper fouled bad when I shot some 110g VMAXs. It was a lot of fun shooting 308 at 3100 fps with the recoil of a .243. Very accurate at 100 yards too. Unfortunately, the consequences were it filled the rifling with copper. It was hell getting it all out
     
  4. MOA

    MOA

    Joined:
    May 16, 2009
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    Shooting 178 eld m and 175 smk at 2625fps.

    I actually considered building a load off the lightest smk for the exact same reason. Havent done it yet though.
     
  5. unclebill

    unclebill

    Joined:
    Apr 4, 2017
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    it's the scope. spend some $$ on a Nightforce or Luepold. people spend all kinds of $ on their guns and nothing on the optics.
     
  6. #40Fan

    #40Fan

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    One, two, skip a few, post something off the wall. He gave the fix. Wasn't what you suggested.
     
    oregonshooter and seymour fish like this.

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