The 20moa base.

Discussion in 'Main Message Board' started by MrBottleneck, Sep 10, 2017.

  1. MrBottleneck

    MrBottleneck Silver $$ Contributor

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    Sorry, I must be having a brain cloud or something.
    I dont usually shoot at 1000 but, last month or so did it for the first time.
    Now, I am going to do it again Oct. It was just so much darn fun. :)

    So, I have a few questions about going to a 20moa base.
    Now according to JBM for my 6br Norma I will need 10mil for me to get to the target at 1000 using the inputed bullet, fps etc etc.
    My flat base Zeroed at 100 yards only gets me just a smidgen over 9mil. till maxed out.

    Now according to Leupold the V3i LRP 8.5-25x50 has 80 moa adjustment. So, that would give me roughly 40moa at mechanical center 40up/40down correct.
    If 10 mil equals 33.75moa why cant I get to the needed 10mil but, only 9mil or 30.75 or so moa.
    So, at 100 my needed mils are currently wasted in down and not used which would equate too 2 mil or roughly 6moa I am lacking?

    Am I correct to assume if I go to a 20moa base I will still be able to get zero at 100?
    I dont shoot a long ranges (or atleast 1000 often) so, its important I can still zero at 100. The perfect scenario would be the 20moa gets me to both 100 and 1000.

    Sorry, if this was not explained exactly as needed but, hope you get the jest of my question.
     
  2. 6.5creed

    6.5creed Silver $$ Contributor

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    20 MOA base will allow a 100 yard zero and get you out past 1000 and then some.
     
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  3. Geno C

    Geno C

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    You have almost 50moa left unused in the erector currently. Adding a 20moa base; given nothing else changes will give you 30moa unused. That's plenty far off the bottom to let you use all the windage in that scope. Shouldn't have any problems running a 20,30, or even 40 moa base and still get 100 yard zero.

    This all assumes your in the relative middle windage wise. If you're at one edge or the other for some reason all the elevation isn't always available.
     
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  4. Milo 2.0

    Milo 2.0 Gold $$ Contributor

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    First, you should actually see if the scope does have the 80moa of travel.
    2nd, you've actually lost close to 3mils, or 9 moa of up travel.
    Repositioning the rings on the base may free some up, most aren't that true. Typically losing 5moa of up travel when zeroing at 100 yards is normal, 9moa a little excessive.
    Like said, a 20moa base will give you what you need, a 30moa base would work too.
     
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  5. MrBottleneck

    MrBottleneck Silver $$ Contributor

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    Hmm, thats really assuming the bases are machined to a very poor standard?
    It would have to machined off 1/16 at one end to another to give me almost 1moa at 1000 and even then I would still be short on travel.
    Dont really see a reason to go through even trying that especially since I lapped them to where they are currently.

    Sounds like 20moa is the way to go for me shorting both long and short.

    On a side not thanks for your fellas input on the base. :)
     
    Last edited: Sep 11, 2017
  6. T-shooter

    T-shooter

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  7. Milo 2.0

    Milo 2.0 Gold $$ Contributor

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    Yes, saying not true was poor wording, meant more mess with ring spacing, or moving to diff slot, your zero will change.
    Also, 1/16" will move things way more than 1 moa at 1K.
     
  8. MrBottleneck

    MrBottleneck Silver $$ Contributor

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    Actually, it would be less then 1moa at 1000 if its 1/16 moa at 100 it would be roughly 5/8 correct at 1000.

    Regardless its neither here nor there. I need a 20 moa base. :)
     
  9. bobinpa

    bobinpa Gold $$ Contributor

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    No need to apologize.......

    If 10 mil equals 33.75moa why cant I get to the needed 10mil but, only 9mil or 30.75 or so moa. You are assuming that your scope is mechanically centered after you zero at 100 and it's almost certainly not.

    So, at 100 my needed mils are currently wasted in down and not used which would equate too 2 mil or roughly 6moa I am lacking? Yes, that's probably exactly what's happening.

    Am I correct to assume if I go to a 20moa base I will still be able to get zero at 100? Yes

    I dont shoot a long ranges (or atleast 1000 often) so, its important I can still zero at 100. The perfect scenario would be the 20moa gets me to both 100 and 1000. It should, but you won't know unless you try. I use Ken Farrell bases and rings whenever possible. In my opinion, they are top notch quality.
     
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  10. Ggmac

    Ggmac

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    The values listed for the scope are when the vertical is perfectly centered .
    Think of a tube inside a tube , if your far left or right your elevation is considerably less . I hope this makes sense , extremely tired !
     
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  11. Turbulent Turtle

    Turbulent Turtle F-TR competitor

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    Sometimes people forget the principle of a canted rail. If your scope has 80MOA of total adjustment, this means that at mechanical 0, provided the mount and rings are able to hold the scope parallel to the bore, you have 40MOA down and 40MOA up at the bore. Using a canted 20MOA rail simply shifts this balance to 20MOA down and 60MOA up. Of course, if you mount the rail the wrong way, you end up with 60MOA down and 20MOA up. (This is only useful if you're shooting from a mountain top or a high building.)

    For your purposes, 60MOA of up elevation should cover all your shooting needs, well, up to about a mile or two. You will probably need several MOAs to get to 100 yards, especially if all the pieces are not perfect. But once there, you will still have 50MOAs or more, provided you don't have lots of windage on the scope.

    The only time you need to worry about not getting a 100yard zero using a canted rail is if the rail has more cant that one half of the adjustment range. Say your scope has 30MOA of adjustment range, 15Down/15Up. A 20 MOA rail will shift that to -5Down/35Up. In other words, if all is as it should be you're still above bore at the lowest possible setting.
     
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