Help with mount issues

Discussion in 'Long Range Scopes and Other Optics' started by DZelenka, Feb 13, 2012.

  1. DZelenka

    DZelenka Well-Known Member

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    I have a Leupold 3.5-10x40 (1") with the CDS turrets. I have good sight settings out to 500 yards but I am getting quite high in my adjustment range. I would like to build some elevation into the base. The knee jerk answer would be to use a 10 or 20 MOA base; however, I find that they are quite tall and I like my scope mounted as low as possible. The second solution would be the Burris signature zee rings, but once again they would be .140" higher than my current set up. My current set up is a 2 piece steel weaver style base with extra low? Burris zee rings. Would it be a reasonable solution to shim the rear base 0.010" and then lap the rings? Shouldn't this give me about 10 MOA of additional elevation? Does anyone see any issues with this approach? Is my thinking off base? Is there another solution that wouldn't raise the scope very much?

    Thanks in advance for the assistance.

    Dan
     
  2. bruce_ventura

    bruce_ventura Well-Known Member

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    Seems to me you're half way there. Just buy the posi-align offset insert kit for the rings you already have:
    Installation Kit
    1 each of +/-.005, +/-.010, +/-.020
    Part number 626019

    This seems too obvious. Am I missing something?
     

  3. KRP

    KRP Well-Known Member

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    He's using standard Zee rings, not Signatures.

    The proposed solution should work, the spacing of the mounts will dictate how much elevation you'll actually get from a given thickness shim.
     
  4. DZelenka

    DZelenka Well-Known Member

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    Do you have a quick formula for calculating the moa correction?
     
  5. KRP

    KRP Well-Known Member

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    Using inches for measurement.

    shim thickness/(ring spacing X .000291)
     
  6. DZelenka

    DZelenka Well-Known Member

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    It looks like .010" is 7.92 MOA. I may try to go with .015". That should be sufficient ofr my purposes.

    Thanks

    Dan
     
  7. Dr. Vette

    Dr. Vette Well-Known Member

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    You may end up with a lot less grip from the rings if you lift the rear and then lap them. Just a forewarning should you see your scope start slipping....

    I just checked the Burris site - the height of the regular Zee rings and Signature Zee rings is the same for the low height - 0.150. I don't even see that Burris currently lists them in "extra low" for the Zees - and I'd find it hard to believe that they'd work even with a 40mm objective.

    Signature ring measurements (bottom of page):
    Scopes - rifle scopes, handgun scopes, hunting scopes by Burris Optics

    regular Zee ring mesurements (bottom of page):
    Scopes-Solid Steel Rings by Burris Optics
     
  8. DZelenka

    DZelenka Well-Known Member

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    Why would there be less grip? Isn't that the purpose of lapping them? My thoughts on lapping the rings is that it would be a way to align the slight angle (and hard edge) created when you raise one ring .010 - .015" above the other.

    You are looking at the wrong rings on the Burris site. Burris doesn't make 1" low signature zee rings. It only makes mediums. You are correct about the extra lows which they apparently don't make any more. I have lows on my rifle.
     
  9. bruce_ventura

    bruce_ventura Well-Known Member

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    Two more thoughts:

    0.14" is about the thickness of a cheek pad for a shotgun. You see where I'm going here.

    Rather than lapping the rings, which might be a lot of work, you could bed the scope with stock bedding compound or JB Weld. There's a youtube video of how to do this. Place a piece of shim stock on the rear ring when you bed the tube. It will be embedded in the compound when you're done.
     
  10. DZelenka

    DZelenka Well-Known Member

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    I know where you are going with the cheek pad. I already have one on the rifle. Increasing its height works. I have that set-up on my 7 SAUM with the 50mm LRT scope. I really like the height of this scope and will endeavor to keep it that way. (hard headed I guess)

    Thanks for the tip on the scope bedding. I will check it out.

    By the way, the Leupold tech told today me that shimming the rear base works just fine and is a method recommended by Leupold. He did say to not go over .030" because it creates an aesthetic issue.

    Dan
     
  11. bruce_ventura

    bruce_ventura Well-Known Member

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    Look for a two part video by a Canadian dude. He has the process nailed. Adding the shim is a mod to his process, but should work fine. A thin strip or two of scotch tape should work - it's just a spacer until the compound sets.
     
  12. Dr. Vette

    Dr. Vette Well-Known Member

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    You're also making an egg-shaped hole when you lap them. Only one portion of the ring will still be 1 inch in diameter - the rest will be larger. Lap a little too far and...

    Sorry about the low size - you are correct.

    I have used the dovetail/windage style of bases (i.e. Leupold style) with medium size Burris Signature rings on a few rifles, and they're right down to the barrel. On every rifle I own with Weaver-style bases and rings, the base always seems to be taller and I have to use a "shorter" ring to compensate. So, a low ring in your case may be needed to match your bases, but a medium ring with the Leupold style of base would work as well. Make sense?

    I've got a 3-9x40 with Weaver style bases and the Signature Zee rings on my Vanguard, and it's nice and low against the barrel, FYI. You might want to try them as it's probably a better option than shimming and lapping in the long run. I also prefer my scopes as low as possible so I can understand what you're after. You can always put a -10 insert in the rear ring and a -20 in the front, lowering the whole thing a bit but also giving you incline.