Determining Actual MOA When Using Burris Signature Zee Rings

Discussion in 'Long Range Scopes and Other Optics' started by DocB, May 20, 2013.

  1. DocB

    DocB Well-Known Member

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    I was doing some research regarding the actual MOA gained when using Burris Signature Zee rings and came across quite a bit of good information. I've tried to compile the nexus of my research. I want to thank everyone who helped me out in this effort. Please feel free to make contributions and corrections as needed. (ps, be gentle, this is my first endeavor! :D)

    Hope this helps some of ya'll, Doc :)

    Determining Actual MOA When Using Burris Signature Zee Rings

    Method 1- Using 100 yd. shift method:*

    > Formula:

    [( Total Offset / Ring Spacing) x 3600] / 1.047 = MOA @ 100 yds

    -Total Ring Offset = Total of Ring Insert Dimension (e.g. Using 0.010 inserts = 0.010 + 0.010 = 0.20)
    -Ring Spacing = Distance rings are spaced apart in inches (measured to 0.001 inches)
    -3600 = Inches in 100 yds
    -1.047 = inches per MOA

    +Example:
    >Using 30mm Burris Signature Zee Rings w/0.010 ring inserts

    • Total Ring Offset = 0.010” + 0.010 “= 0.020”
    • Ring Spacing = 3.546” (picatinny standard rail slot spacing = 0.394”, 10 picatinny slots = 3.940”, therefore 9 picatinny slots = 3.546”)
    • [(0.020 / 3.546) x 3600] / 1.047 = MOA
    • [(005640157) x 3600] / 1.047 = MOA
    • [20.3045652] / 1.047 = MOA
    • 19.393089 = MOA

    Therefore using 30mm Burris Signature Zee Rings, MOA gain using standard picatinny rail is:

    21.7 MOA @ 3.152” spacing ( 8 standard picatinny slot spacing)
    19.3 MOA @ 3.546” spacing ( 9 standard picatinny slot spacing)
    17.4 MOA @ 3.940” spacing (10 standard picatinny slot spacing)


    Method 2 – Using arc tan Method:**

    > Formula:

    Arc tan ( A / B ) / 0.0167 = MOA

    -A = Total Ring Offset = Total of Ring Insert Dimension (e.g. Using 0.010 inserts = 0.010 + 0.010 = 0.20)
    -B = Ring Spacing = Distance rings are spaced apart in inches (measured to 0.001 inches)
    -0.0167 deg (or 1/60 degree equivalent to 1 MOA)
    -Arc tan = arc of the tangent


    +Example:
    >Using 30mm Burris Signature Zee Rings w/0.010 ring inserts

    • Total Ring Offset = 0.010” + 0.010 “= 0.020”
    • Ring Spacing = 3.546” (picatinny standard rail slot spacing = 0.394”, 10 picatinny slots = 3.940”, therefore 9 picatinny slots = 3.546”)
    • Arc tan (0.020 / 3.546) / 0.0167 = MOA
    • Arc tan (0.005640157) / 0.0167 = MOA
    * Using a scientific calculator: (0.00560157 {inv tan}) to obtain arc tan result = (0.323153818)
    • 0.323153818 / 0.0167 = MOA
    • 19.3505 = MOA

    Therefore using 30mm Burris Signature Zee Rings, MOA gain using standard picatinny rail is:

    21.7 MOA @ 3.152” spacing ( 8 standard picatinny slot spacing)
    19.3 MOA @ 3.546” spacing ( 9 standard picatinny slot spacing)
    17.4 MOA @ 3.940” spacing (10 standard picatinny slot spacing)

    As is evident, the further apart your Burris Signature Zee Rings are the less MOA advantage you will obtain. If you are using 1inch Burris Signature Zee Rings two counter opposed 0.020 inserts might be recommended to obtain 20 MOA with greater ring spacing.

    I utilize the 30mm Burris Signature Zee Rings with the 0.010 inserts because they, along with 0.00 inserts, are the only inserts currently supplied. Therefore to obtain a 20 MOA advantage a closer ring spacing of 3.152 inches or 3.546 inches must be used. Apparently, I assume, this closer ring spacing is the reason Burris has ‘beefed’ up the 30mm rings when compared to the 1inch rings.

    When using Burris Signature Zee Rings always ensure the inserts are opposed, with the ‘fat’ insert on the bottom in the rear ring, and ‘fat’ insert on top in the front ring. This lifts the rear and lowers the front of the scope to obtain increased MOA and increased scope area.


    *extracted from Elevation Shift with Burris Sig Rings within AccurateShooter.com
    **found in LongRangeHunting.com online magazine forum. I wrote down the formula but can’t find the thread to reference. My Bad.
     
  2. JW74

    JW74 Well-Known Member

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    Jun 12, 2014
    Great post! Thanks for the info.
     

  3. Fishkat

    Fishkat Well-Known Member

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    Feb 3, 2015
    Thanks for the post, quite informative and something I have never considered. Learned something new.
    How do you like the zee rings?
     
  4. gohring3006

    gohring3006 Well-Known Member

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    Good info, I pinned it to my phone for future reference. As for the question about liking the Burris rings, they are a brilliant idea, they are very sturdy steel rings. The inserts are a solution to alot of scope problems other than elevation. They also keep my expensive scopes from being marred. The only complaint is the back order of the inserts.
     
  5. Rich Coyle

    Rich Coyle Well-Known Member

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    Aug 14, 2013
    The other day I mounted scope that I could not get sighted in. I switched to Burris Signatures and used a +20 in one side and a -20 in the other in a vertical orientation in the rear ring. Worked like a charm. While I was at it I used a -10 in the bottom and a +10 in the top of the front ring to bring the centered crosshair almost to sighted in without adjusting the scope.:)
     
  6. 7magcreedmoor

    7magcreedmoor Well-Known Member

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    May 23, 2012
    My brain hurts from all that math stuff. I take a more practical (for me at least) approach. I install the rings lined up vertically, go to the range and zero the rifle, go back to the workbench, attach my collimator and note the reticle position against the grid, pull the scope and reset the internal adjustments to center (mostly I want the windage turret centered) then turn the offset inserts to put the reticle back on the grid just as it was (for windage) then set the elevation turret to zero the vertical again. On my 20 MOA rail I end up within one rotation of the bottom of turret travel.