Anyone seen this happen with their rifle scope?

Discussion in 'Long Range Scopes and Other Optics' started by kraky2, Aug 15, 2005.

  1. kraky2

    kraky2 Well-Known Member

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    Maybe it's me and I'm crazy but here's my story. I have a 300 wby ultralight that 's never been a great shooter--not awful either but I'm trying to get better 300 yd groups with it. OK, it's an ultralight which is a risky proposition to start with. But the other day at the range I noticed on my ballistic plex (Burris fullfield II)scope at 300 yds that depending on where I position my head and eyes the cross hairs seem to wander with my eye position. I'm shooting at 5" orange dots with a black center and can see the center pretty clear. But by moving my head around I can make the crosshairs move almost all the way around that 5" dot. (This being done with a solid fron rest and rear sandbag holding the gun virturally rock solid). I checked one of my Leupolds when I got home and I swear it doesn't move hardly at all---maybe an inch if I really move out of position behind my scope.

    If what I think is happening ....IS happening ...this certainly can't be good for shooting good groups. I'm thinking this is what they call "parralax"?? Anyhow has anyone else experienced this with their fullfield II or are my 48 year old eyes going bad??
     
  2. Michael Eichele

    Michael Eichele Well-Known Member

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    It is indeed called paralax. Most scopes are either paralax adjustable or paralax free from a certain yardage or to a certain yardage.
     

  3. Jimm

    Jimm Writers Guild

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    No, you are'nt crazy ! just Kraky /ubbthreads/images/graemlins/laugh.gif
    Hey man , there are loads of guys here that can do this better , but I just happened along first.
    Parallax, yes ! I am not familiar with your scope but what you are experiencing sounds like incorrect adjustment of same for the distance you are shooting at.
    If the scope you are using has an adjustable objective ( whether side focus or on the objective lens , doesn't matter)you would want to adjust the parallax,read focus , at whatever distance you are shooting at and the process involves finding the place that where moving your head causes the crosshairs to move the least or not at all.
    Scopes with fixed parallax are usually set around the hundred or so mark, Leupold scopes can be sent to the custom shop to have the parallax adjusted to the clients preference.There is so much more on this subject that I think it would be best for me to leave it with clearer heads and those with more understanding. /ubbthreads/images/graemlins/grin.gif I'm still waiting for someone to encapusulate the " parallax " thing in a way that I would want to save it for future enquirers.
    Anyways , now that I've confused the heck out of you, I'll see you later ,

    Jim Brown
     
  4. Buffalobob

    Buffalobob Writers Guild

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    If you go up to "handloading" where Kidblast is having a problem with his 7 RUM. What you describe is what I try to explain to him.

    The way you get by with a non-adjustable scope is with a perfect repeatable stock weld so your eye position is always the same. Practice with shooting mechanics is very necessary.

    My best estimate is that bad stockweld and bad paralax together is about 0.5 MOA of addtion to group size at 500 yds.
     
  5. davewilson

    davewilson Well-Known Member

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    the way i've always dealt with this is to move your head back away from the scope until you have a much smaller field of view to look through.you'll also have a black area around the field of view.when shooting,center the cross hairs in the field of view,and also center the field of view inside the black area.this is how you can line up your eye looking through the scope the same place every time.now you know why they sell scopes with parralax adjustments!
     
  6. LB

    LB Well-Known Member

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    Yeah, and don't necessarily believe the marks on the ring, they can be way off. A decent battlesight setting is usually infinity, but check it. LB
     
  7. bucknutz

    bucknutz Well-Known Member

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    ah ha! now the real secret is out! what about using windage bases and burris magnificant zee inserts to adjust to your optics center?the .25-06 is ready for the next round,while the AI is having FUN! ao is usually needed for over 10-12x