Scope jumps

Discussion in 'Gunsmithing' started by Limbic, Oct 16, 2008.

  1. Limbic

    Limbic Well-Known Member

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    Jun 26, 2008
    My Sendero has just a touch of receiver bedding. When I was at the range today I noticed that when I would practice dry fireing the crosshairs would jump off of the target about an inch. What gives? I call myself checking all the mounts and screws. Is it because the barrel is free floated?

    Man I hope this helps account for my poor groups. Anywhere from .8inches to 2.5 inches with factory ammo.
     

  2. phorwath

    phorwath Well-Known Member

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    Hey,

    I'm no expert on scope crosshairs jumping around like that, but check out this thread:

    http://www.longrangehunting.com/forums/f18/night-force-scopes-34443/index2.html

    There was some talk of crosshair movement in a scope by another forum member in that thread. Good luck. If I saw my crosshair jump around on a dry fire I'd be scratching my head too!
     

  3. MagMan

    MagMan Well-Known Member

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    Dec 20, 2002
    Double and triple check your rings.

    I was beating my head because mine wasn't holding a good zero or shooting well for that matter. I sent it in to Ken and within a week they had already inspected it and found no flaws. After talking with Ken for a while he had decided it was my rings. I bought NF Ultra lite rings and installed them. Didn't get any better, I later lapped them and it held for a while but then went crazy again. I pulled them apart once again, relapped and glued the scope in with liquid electrical tape.....all has been holding well.

    I've had 4 different scopes (rings actually) doing the same exact thing. I think with the weight of these NF's and the recoil from braked bigguns a little extra attention should be paid.

    Rings would be my #1 guess and body alignment would be my second guess.
     
  4. Cruizin

    Cruizin Well-Known Member

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    Dec 25, 2006
    It's my understanding that a scope should do this. After all the scope is a tube with a tube in it that is supported and floated by springs. Its going to move after recoil or a dry fire but if it doesn't return to zero then you have a problem. This is the main difference between a high dollar scope and a cheap one.
     
  5. Cruizin

    Cruizin Well-Known Member

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    Dec 25, 2006
    Then there are other issues to consider like the wear of the different metals that the tube and the springs are made of. Also the metals used in the turrets need to be hardened or chosen correctly to prevent wear and gauling. These factors can contribute to a scope not functioning properly. This is just my understanding of scopes based on my limited knowledge of them, but I do work with different metals, and there hardness in different applications on a daily basis for what it's worth.

    The big question is does it return to zero?