Why do the crosshairs jump?

Discussion in 'Long Range Hunting & Shooting' started by tunacan, Jan 25, 2011.

  1. tunacan

    tunacan Well-Known Member

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    while at the range and dry firing my gun I noticed quite a bit of movment of the crosshairs after the trigger was pulled.

    Is this indicitive of something? Form?

    I can shoot tiny groups and my equipment is solid.

    Trigger is well adjusted

    The gun is built well with quality components and the scope is a Vortex Viper.

    Bases, rings, screws are torqued to spec.

    Thanks for your help
     
  2. liltank

    liltank Well-Known Member

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    I find when dry firing that I still get a little movement with each pull. The firing pin spring is quite robust, so I have a feeling we are seeing a natural movement from the rifle with this tension being released. The more important part is making sure it moves in the same direction each time.

    Tank
     

  3. Kevin Cram

    Kevin Cram <b>SPONSOR</b>

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    What your seeing is a vibration being caused by something more than likely in the fire control. If you dry fire the rifle you can probably watch the bolt handle jump a little. Your timing is off. Your rifle can still shot well but maybe not up to its full potential. Its kind of like a car engine. It will run if the timing is off a little but not to its full potential.
     
  4. rscott5028

    rscott5028 Well-Known Member

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    It's part mechanical and part shooter induced.

    As stated by other posters, the chances are that you are not shooting to your full potential.

    I think I've heard Darrel Holland say that the bullet will remain in the barrel ~1/24,000 of a second and for about ~3/8" of recoil during which any movement will affect the POI.

    If the bore tracks exactly rearward, no big deal. But if it moves left/right/up/down especially with any inconsistency, your groups will reflect it.

    I was always told growing up not to dry fire as you could break a firing pin. Perhaps that was due to older rifles and/or safety concerns.

    Practicing safely with modern rifles is a good thing. I also find it useful to have my son dry fire before attempting a long shot at game. It helps to settle nerves and verify whether he's got a decent rest/position.

    A lot of the long range shooting books and videos go into detail about perfecting your technique. And, I think there are tweaks that competitors use to tune their actions and firing pins etc to squeeze out that extra tiny amount of precision.

    ...wish I could give specific advice
    but, here are some things to ponder (from a non-expert)...

    light weight rifle
    timing of the bolt
    trigger adjustment
    trigger control - straight to the rear
    don't wrap thumb around stock
    bone support/muscle relaxation
    stable bench, front bag, bipod
    breathing
    rear bag placement and square
     
  5. edge

    edge Well-Known Member

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    How much is "quite a bit of movement"??

    Try this:

    Look through the scope but don't touch the rifle except the trigger...not even your shoulder!
    When the trigger breaks do the crosshairs still move the same amount?

    If no then you are torquing the rifle when shooting.

    If yes, then the first thing I would check would be your rest. If a rifle is on a good set of bags then it really should not jump around much at all...IMO.

    edge.