20 moa bases

Discussion in 'The Basics, Starting Out' started by hjl, Mar 8, 2006.

  1. hjl

    hjl Well-Known Member

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    Hi,
    Working on the theory that the only stupid question is the one you don't ask.Here is my stupid question .How do 20 moa bases work ie what do they do?
    Thank you for your help.
    Regards
    hjl
     
  2. winmagman

    winmagman Well-Known Member

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    Tapered bases will tilt the front of the scope down (toward the barrel), this causes you to have to raise the barrel to get the crosshair on the target which will make the point of impact high. Then when you have to dial the turret down to zero the point of impact which will leave you more room to dial back up for longer shots.

    Chris
     
  3. hjl

    hjl Well-Known Member

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    winmagman,
    Thank you for your reply.What are all the cross slots for on 20 moa bases?
    Regards
    hjl
     
  4. Jimm

    Jimm Writers Guild

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    hjl ,

    The bolt that is part of your scope ring fits in this slot . Ummm, you know , Weaver style rings /ubbthreads/images/graemlins/cool.gif

    Jim B.
     
  5. hjl

    hjl Well-Known Member

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    jimm,
    Thank you for your reply.
    So they are for weaver style rings. That is good . Why so many slots ?
    Regards
    hjl
     
  6. winmagman

    winmagman Well-Known Member

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    The number of slots allows more options for ring location, some scopes are longer than others and some have less room between the occular lens and adjustment turrets or between turrets and objective lens, just makes it easier to get the proper eye relief.

    Chris
     
  7. hjl

    hjl Well-Known Member

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    winmagman,
    Thank you for your reply.It is making sense to me now.
    Can you get 20 moa bases for a rimfire rifle?ie 3/8 dovetails.
    Regards
    hjl
     
  8. winmagman

    winmagman Well-Known Member

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    Good question, I suppose someone does or could make them, but I can't imagine the need for 20 moa bases on a rimfire rifle.

    Chris
     
  9. hjl

    hjl Well-Known Member

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    wimmagman,
    The idea of 20 moa bases on a rimfire [22lr] came to me for 200 yard target shooting.Maybe not a good one. At the moment I use my nightforce with it's np1-rr reticle to hold over.
    Regards
    hjl
     
  10. Buffalobob

    Buffalobob Writers Guild

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    Being as you have started with very simple questions, I will give you a few very simple pieces of advice. Its free so don’t complain.

    First make sure you want and need 20 MOA bases. I am planning on trying a 350-450yd assault with a 22 rimfire on a local acquaintance of mine in the next four or five days now that the weather is warm and he is poking his head out. I checked my dialup and can marginally get to about 350 yds without any adjustment to the bases.

    Second, depending on which gun it is and you are a little skimpy on critical information in that category, You can just shim and bed the base you have if it is one piece.

    Third, until you have a scope mounted you may not be able to tell the alignment of the top of the receiver in relation to the barrel. It is entirely possible that your gun left the factory with some receiver slope that either helps or hinders.

    Fourth, be careful and don’t get the gun set up for five hundred yds and not be able to dial back do to 25 yds.

    There is probably a fifth and sixth but I will let you have some fun on your own.
     
  11. frequent misser

    frequent misser Well-Known Member

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    hjl-
    I just set up my old marlin for the same thing. I used the bushnell 10x40 3200 since its got 100 inches of adjustment at 100. You could use bkl bases which let you use a weaver ring and then mount burris signatures rings with inserts. Longrange with the highpower seems a whole lot easerier after the quarter mile 22 longrifle shot.
     
  12. Buffalobob

    Buffalobob Writers Guild

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    With a 100 yds zero you only need about 10-15 MOA to get to 200 and maybe 30-40 to get to 300yds. Lots of different speeds of ammo out there so it is hard to tell and the BCs are all goofy and the thing goes subsonic at about 100yds so it is all weird anyway. Some people advise starting off subsonic so you don't fool with the transtion.
     
  13. winmagman

    winmagman Well-Known Member

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    Well no wonder I couldn't imagine a use for 20 moa bases on a rimfire, when I think of 300 yds I think .243 /ubbthreads/images/graemlins/grin.gif /ubbthreads/images/graemlins/grin.gif /ubbthreads/images/graemlins/grin.gif
     
  14. hjl

    hjl Well-Known Member

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    buffalobob,
    Thank you for your reply & advice.The bit about the receiver hindering has got me thinking.
    Regards
    hjl