MOA Base for Sightron Series III

Discussion in 'Long Range Scopes and Other Optics' started by mattallen, Oct 9, 2013.

  1. mattallen

    mattallen Member

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    Ok, I finally decided that I was going to go with the Sightron for the money and got a Series III 8-32X56 I got the mill dog reticle. According to my tracking it has 11.5 mils each way. That equates to 11.5x3.438=39.5 moa each way. So I was wondering should I go with a 30 moa base or 20 moa base I no the scopes track the best in the middle of the scope. Its going on a 338 lapua so it will be getting stretched out a lot thanks for you input matt allen
     
  2. bruce_ventura

    bruce_ventura Well-Known Member

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    You have a custom rifle, so I would expect that the barrel is installed parallel to the receiver. Barrel vibration should not be too bad with a heavy profile barrel, so the live fire 100 yd zero should be within 10 MOA of boresight. I would go with the 30 MOA base. Worse case is that you may need to zero at a longer range.

    That will leave you with approximately 70 MOA of up adjustment, which is in the ball park of what you need to get to 1500 yds, depending on load and altitude. Your zero should be within one turn or so from the limit stop, so finding your zero will be easy.

    I recommend that you not leave the scope elevation set for your zero range during storage. That setting has the erector tube spring nearly fully compressed, which could weaken the spring over time. Better to leave the turret set to the mechanical zero or even closer to the long range limit stop. Then set it to zero when you pull it out of the case to start shooting.
     

  3. BMF

    BMF Well-Known Member

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    I recommend that you not leave the scope elevation set for your zero range during storage. That setting has the erector tube spring nearly fully compressed, which could weaken the spring over time. Better to leave the turret set to the mechanical zero or even closer to the long range limit stop. Then set it to zero when you pull it out of the case to start shooting.

    Is that all scopes or just sightron?
    Brent
     
  4. BMF

    BMF Well-Known Member

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    QUOTE.........I recommend that you not leave the scope elevation set for your zero range during storage. That setting has the erector tube spring nearly fully compressed, which could weaken the spring over time. Better to leave the turret set to the mechanical zero or even closer to the long range limit stop. Then set it to zero when you pull it out of the case to start shooting.

    Is that all scopes or just Sightron? Thanks Bruce
    Brent
     
  5. bruce_ventura

    bruce_ventura Well-Known Member

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    Yes, for all scopes with conventional erector springs located near the turrets.

    Swarovski Z5 and Z6 scopes are an exception. They have coil springs located near the eyepiece. They aren't compressed as far at max elevation.
     
  6. trebark

    trebark Well-Known Member

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    While I would agree that you should go with a 30moa base in order to get maximum travel out of your scope, I disagree that you would need 70moa to get to 1500yards. Shooting the 250grain Scenar (G1 BC =.675) at 2700fps 70moa would get you to 1625yards.