20 MOA bases help

Discussion in 'Long Range Scopes and Other Optics' started by coyotekillerSD, Jun 27, 2010.

  1. coyotekillerSD

    coyotekillerSD Member

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    ok i got my rifle set up with 20 moa base and then i went to sight it in. i got it shooting 2" high at 25 yards and i cant get to paper at 100 yards. how high do i need to be at 25 yards. i do not own a boresighter so i have to shoot to adjust.
    also once i get zeroed how does the 20 moa affect poi at longer ranges? of course i will keep shooting and learning any help here is greatly appreciated.
     
  2. bigngreen

    bigngreen Well-Known Member

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    If I do shoot at 25 I have to shoot an inch low to be a little high at 100. I usually just set the gun up stable and pull the bolt and at a 100yrds I should see my orange dot in the bore and I adjust the scope to match, this usually gets me within a few inches and I can measure with my reticule and make the final adjustment.
     
  3. Eaglet

    Eaglet Well-Known Member

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    Because there is so much lack of info. in the question, like the caliber you're shooting, what bullet?, what velocity?, is it it factory ammo, reloads? etc, etc.
    My answer would not be much accurate.

    With a hight power rifle,
    2" high at 25 yards you're probably zeroed at 635 yards, you'd be about 12.5" high at 100 yards.

    What scope are you using? What's the total vertical adjustment for it?
     
  4. coyotekillerSD

    coyotekillerSD Member

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    im shooting a 7mm rem mag with 168gr vlds im not sure how much adjustment is built in it has a 30mm tube and adjusts at 1/8 moa.

    i do have rings that are too high right now so my scope is about 2.5 inches above the bore. when i replace them it will come down some but not much.

    anyway my theory is that it is shooting low at 100 yds because of the base having 20moa. its a one peice base so it only goes on one way.

    when i shoot it out at about 100 yrds. it was way low. i brought it back in to 25 yards shot again and got it at 2" high
     
  5. Eaglet

    Eaglet Well-Known Member

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    Something is very wrong with the information I'm getting. Please let me explain:

    I'm using the following:

    MV = 2800 fps
    Zeroed = 25 yards
    Impact = 2.0 in. high
    Bullet VLD Berger 168
    Elevation: Sea Level

    There is no way for the bullet to strike 2" high at 25 yards and then low at 100
    yards. Please look at the table...

    [​IMG]
     
  6. toader

    toader Well-Known Member

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    Get a flat (0 MOA) base & you'll be good to go. If you scope is limited in elevation travel, you may never be able to get a 100 yd zero with the 20 MOA base.

    What scope are you using??
     
  7. Eaglet

    Eaglet Well-Known Member

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    Even if the scope did not have much adjustment, he should be able to zero in at 200 yards.

    Let's say the scope he is using only has a grand total of 30 moa. That'd be 15 moa from center... So using a 20 moa base he sould bearly be able to zero at
    200 yards and have 29 moa left of upward vertical adjustment. :)

    If this was to be possible, then he would be 1.2" hight at 100 yards and 1.1" low at 25 yards.

    He says he's low at 100... and 2" hight at 25 yards... That I don't understand!
     
  8. toader

    toader Well-Known Member

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    Not understanding his problem either??

    I know I have tried to get a 100 yd Zero with a S&B scope that was very limited in elevation travel & a 20 MOA base - that didn't happen. Had to go to the 0 moa (flat) base to get it to work.


    Still wondering what scope he's using?? Like you said, with a 20 MOA base, a 200 yd Zero should be no problem at all!!
     
  9. coyotekillerSD

    coyotekillerSD Member

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    hey eaglet it is entirely possible that i am to blame for this. you see i rushed to the range as soon as i put the scope on even though it is much to high to get any cheekweld. so i was using my offhand as a raised cheekpiece. which probly caused me to be horribly inaccurate at anyrate.

    i just dont know, like i said i was shooting exactly where i wanted to during my "boresighting"

    but just to check the scope is supposed to be lower on the front than on the back with the 20 moa right.
     
  10. Eaglet

    Eaglet Well-Known Member

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    I have had riflescopes mounted at 2.5" high because I could not find lower rings. A cheek piece will solve the problem. Right now my scope on my 338 Edge is 2.1 which is pretty normal I'd say, it's still too high and I'm ordering an adjustable cheek piece.