20 MOA Rail Confirmation

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  • Please let me know if I'm thinking correctly on the installation of a 20 MOA rail...
    Install 20 MOA rail with the thick part to the rear.
    Install scope on rail and set to proper eye relief.
    Lower the scope setting by 20 MOA.
    Bore sight scope.
    Take to range, establish zero and reset elevation knob to zero.

    Do I have this correct?
     

    ToolAA

    Ultimate Member
    MDS Supporter
    Jun 17, 2016
    10,500
    God's Country
    What Boats said was correct you are raising the relative position of the reticle, but in order to do that, the taller part needs to be towards the front of the rifle.
     

    rbird7282

    Ultimate Member
    MDS Supporter
    Dec 6, 2012
    18,535
    Columbia
    What Boats said was correct you are raising the relative position of the reticle, but in order to do that, the taller part needs to be towards the front of the rifle.


    The taller part of the rail needs to be at the rear of the rifle not the front.


    Sent from my iPhone using Tapatalk
     

    Occam

    Not Even ONE Indictment
    MDS Supporter
    Feb 24, 2018
    20,239
    Montgomery County
    Picture artillery in the field. You're looking straight out across the battlefield through your sights, but the barrel on that cannon needs to tilt way up to lob that long-range shot.

    Here's another of my incredible, award-winning illustrations.

    20moa.jpg
     

    Growler215

    Ultimate Member
    Dec 30, 2020
    2,170
    SOMD
    The taller part of the rail needs to be at the rear of the rifle not the front.


    Sent from my iPhone using Tapatalk

    Agree.

    When I'm sighting in my rifle I adjust the crosshairs to where the bullets are hitting. If they are hitting high, I adjust "up." At long range they will be hitting way low, so I adjust "down." At some point i run out of adjustment in the "down" direction. The only way to have the crosshairs go any lower is to have the scope tilted down.

    By raising the rear of the scope 20 moa I've traded some of the excess upward adjustability of the scope for 20 moa more downward adjustability. This is done when I sight in at 100 yds and adjust "up" 20 moa to match where the bullets are hitting.

    At least that's how I'm picturing it....
     

    Boats

    Beer, Bikes n Boomsticks
    Mar 13, 2012
    4,073
    Howeird County
    The taller part of the rail needs to be at the rear of the rifle not the front.


    Sent from my iPhone using Tapatalk

    thats a big negatory, good buddy.

    For starters, on most rifles, the screw spacing won't allow this.

    Second, the up and down arrows on your elevation turret refer to point of impact, not recticle direction of movement. When you dial in a heaping dose of UP elevation, the recticle actually moves down (decreasing the distance between the cross hair and the muzzle, effectively raising the muzzle in relation to the cross hair, and raising the point of impact)

    Hope this helps
     

    E.Shell

    Ultimate Member
    Feb 5, 2007
    10,244
    Mid-Merlind
    What Boats said was correct you are raising the relative position of the reticle, but in order to do that, the taller part needs to be towards the front of the rifle.
    You are physically raising the reticle position to bring the point of impact down by 20 minutes to counteract the installation of the tapered base with the tall side to the rear.

    Please look at Occam's diagram.


    thats a big negatory, good buddy.
    Don't be a mud duck. Please look carefully at Occam's (correct) illustration above and re-think your position, and the position of your base.
    For starters, on most rifles, the screw spacing won't allow this.
    True that most rifles' screw spacing differences won't let you reverse the base. Luckily...
    Second, the up and down arrows on your elevation turret refer to point of impact, not recticle direction of movement. When you dial in a heaping dose of UP elevation, the recticle actually moves down (decreasing the distance between the cross hair and the muzzle, effectively raising the muzzle in relation to the cross hair, and raising the point of impact)
    True, but only serves to confuse new/unfamiliar shooters when mixed into "zero" conversations.
     

    boothdoc

    Ultimate Member
    MDS Supporter
    Mar 23, 2008
    5,133
    Frederick county
    On the rear. This way you use more of the whole scopes elevation movement. The fist time I mounted a scope I went back and forth in my head about it for sometime. It almost seems counter intuitive in some ways.
     

    E.Shell

    Ultimate Member
    Feb 5, 2007
    10,244
    Mid-Merlind
    On the rear. This way you use more of the whole scopes elevation movement. The fist time I mounted a scope I went back and forth in my head about it for sometime. It almost seems counter intuitive in some ways.
    Visualize keeping the scope always on target, and then moving the rifle butt downward by adding more height/slope to the rear of the rail, thus raising the muzzle and getting a 'head start' on rifle elevation.
     

    outrider58

    Eats Bacon Raw
    MDS Supporter
    Jul 29, 2014
    49,818
    Sounds to me, some people need to go back and relearn how to shoot irons. ;)
     

    rbird7282

    Ultimate Member
    MDS Supporter
    Dec 6, 2012
    18,535
    Columbia
    thats a big negatory, good buddy.

    For starters, on most rifles, the screw spacing won't allow this.
    it will if the base is made for that rifle. I switched from a 20 MOA base (which was stock)to a 30 MOA base on my Ruger Precision because I ran out of elevation adjustment on my scope at about 1050 yards. Now I can dial up out past 1200 with no issues
    Second, the up and down arrows on your elevation turret refer to point of impact, not recticle direction of movement. When you dial in a heaping dose of UP elevation, the recticle actually moves down (decreasing the distance between the cross hair and the muzzle, effectively raising the muzzle in relation to the cross hair, and raising the point of impact)
    Correct which is basically the same thing that happens when you put on a scope base that has built in elevation, it moves the reticle down and raises your point of impact

    Hope this helps

    See above
     

    ToolAA

    Ultimate Member
    MDS Supporter
    Jun 17, 2016
    10,500
    God's Country
    You are physically raising the reticle position to bring the point of impact down by 20 minutes to counteract the installation of the tapered base with the tall side to the rear.

    The taller part of the rail needs to be at the rear of the rifle not the front.

    Wow….all these years I was blaming my spotter….I owe some people apologies.



    All seriousness, I’m a little embarrassed I got that wrong but man enough to admit it. Thanks for the clarification.
     

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