Gun will not Bore sight???????

Discussion in 'Technical Questions & Information' started by upssmann, Apr 3, 2012.

  1. upssmann

    upssmann New Member

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    Got my Leupold vx3 back from Leupold and gun shop remounted it and now tells me it will not bore sight , dosent have enough windage adjustment, They even took another scope same as mine and they had same problem? they looked and the mounts and rings and that didnt help either, they are confussed along with me, the scope was shot and sighted in last year before it was sent away? any ideas why the gun is causesing this, he talked about sciming the scope but I perfer not to ??????
  2. BETH

    BETH Well-Known Member

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    wow i can't help but i am sure someone will be along
  3. BETH

    BETH Well-Known Member

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    what do u think Jack
  4. BETH

    BETH Well-Known Member

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    while we are waiting can u post a picture and tell us what kind of gun
  5. carver

    carver Moderator

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    Are they using a laser bore site, or an optical bore sighter?
  6. upssmann

    upssmann New Member

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    they are using an optical bore sighter, the gun is a xbolt 7m-08 someone on another site said that the leupold base and rings are windage
    adjustable saying u can adjust the windage with the base screws?
  7. upssmann

    upssmann New Member

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    the gun is a browning 7=08 xbolt stain less Leupold rings and bases . Leupold vx3 3.5 by 10
  8. Helix_FR

    Helix_FR New Member

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    Yes the rear base has screws on the left and right side if you have the cam lock type. They can be used to make gross adjustments to the scope for windage that way you use the scope adjustments for fine tuning. May I suggest taking it to someone that can boresight that knows what they are doing;):D Its not the scope, is the way the scope is mounted.
  9. cpttango30

    cpttango30 Guest

    I am going to agree with Helix. They need to adjust the rear base if it has the adjustable base on it. It is very easy to not take them down evenly and have the whole thing out of whack. I bet that is what happened to your scope last year is that you have it torqued out of line and shooting it broke it.
  10. JLA

    JLA Well-Known Member

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    Thats why I prefer gamereaper one piece mounts. Everything is as centered as the screws in the action top.
  11. LDBennett

    LDBennett Well-Known Member

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    If the gun is a bolt gun then remove the bolt and look down the bore for bore sighting. I don't know how may guys I have helped at the range bore sight guns that gun shops supposedly bore sighted with a collimator (optical bore sight tool) incorrectly.

    Leopold bases have screws on each side of the rear mount to make windage adjustments but........ the front mount has to be twisted into alignment with the rear mount when making such adjustment to the rear windage or you put the scope tube in a bind and can cause damage internally. DO NOT use the scope tube to do that alignment. You have to use a bar that is lathe turned to the scope tube diameter to assure the front mount is in alignment with the rear mount before you ever put the scope on the gun. If you can not get the windage adjusted with the scope itself you have to pull it off the gun adjust the rear windage, use the bar to align the front mount with the rear, then remount the scope and adjust the windage in the scope. It is a trial and error process.

    Another option, if it is really the gun's tapped holes in the receiver that is at fault, is the Burris mounts that have offset plastic insert to make up the error in the gun.

    If this is all too much for you take the gun to a real gunsmith.

    In all the years of mounting my scopes and those of others I have not had trouble getting the windage right. The few Leopold adjustable windage mounts that I have used have been fiddley but I have never failed to get a scope mounted with them. I prefer other's mounts as the windage adjustment is not really necessary on a modern gun.

    I have had to shim bases up to get the elevation right because the receivers' top surface on a couple of my guns are not parallel to the bore and I ran out of elevation adjustment on the scope. One of those was a 10/22.

    Home made drill and tap jobs often lead to mounts that are grossly out of alignment with the bore. I put an over the bore mount on a Mosin Nagant and the top of the receiver, unknown to me, was not in alignment with the bore but what do you expect from a Russian gun from the 1930's? Those guns are a bit crude to say the least. Modern guns rarely have scope mounting problems. I have one CZ that came with mounts and I had to swap the supposedly identical mounts around to be able to zero the gun. CZ are great guns and that one stumped me.

    LDBennett
  12. oneoldsap

    oneoldsap New Member

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    Has anyone here tried shimming a base on an X-Bolt ? Do you need seperate shims for both sets of holes , they're 4 screw bases . Will raising the base move the screw holes out of alignment , as the receiver isn't flat , front or back ? An inquiring mind wants to know !
  13. LDBennett

    LDBennett Well-Known Member

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    You know it does not take much in the way of a shim to make a big change on the target. Typically it is about 600 to one at 100 yds. I would think that any shimming for any gun would be minuscule and not effect the alignment of the holes. But if everything goes wrong there is always the Burris rings with the offset plastic inserts that make bigger changes than you would want to do with shimming.

    http://www.burrisoptics.com/sigrings.html



    LDBennett
    Last edited: Apr 4, 2012
  14. Helix_FR

    Helix_FR New Member

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    Shimming will only help a elevation problem. Correct the windage problem with the screws
  15. upssmann

    upssmann New Member

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    gun smith remounted the scope today and he said he tapped on the adjustment knobs, and the scope became adjustable again it seemed to be stuck, so he bore sighted it and showed me all the adjustment it had and I shoot it and it was shooting just fine at the range so thanks everyone for ur help....
  16. upssmann

    upssmann New Member

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    Thats a good question because he told me he only has shimmed a gun with 2 screw holes and he would have to put shim on that would use 4 , so it would be knew for him to.....
  17. Helix_FR

    Helix_FR New Member

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    Usually when you shim any bases, you only shim 1 or if its a 1 piece base you shim the front or back side. Shimming both is counteractive. Your raising both the same height, its no different than not using shims at all. most split bases use 2 holes per base so yes, you shim both holes usually using 1 piece of shim with 2 holes in it.
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