AR scope trouble ...... HELP

Discussion in 'AR-15 Discussion' started by larich29, Aug 29, 2013.

  1. larich29

    larich29 New Member

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    I just got a Rock River Arms Entry Tactical .223 AR. I went out to shoot today and had some trouble getting the scope sighted in. It's a Vortex strike fire red dot scope. . I set it in from 30 yards and it was about an inch high (which I wanted), I moved back to 60 yards and it was shooting a FOOT high. So I adjusted it and it shot great. Then I walked back up to 30 yards and it shot 10 inches low. I really don't know what to do with it.
     
  2. CamoToe1

    CamoToe1 New Member

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    Is your Red Dot mounted on a carry handle by any chance? If a scope is mounted a lot higher than the bore it can really affect POI at close range.
     
    Last edited: Aug 29, 2013

  3. KG7IL

    KG7IL Active Member

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    Are you expecting POA/POI/LOS to be the same at all distances?
    POA = Point of Aim
    POI = Point of Impact
    LOS = Line of Sight

    What is your height above bore for your red dot. (Scope Height)
    What load ?

    I ran a ballistic graph and that doesn't quite explain the 10" deviation over 30 yards difference.

    How many shots were in each group? what was the group size?

    Red Dot's notoriously have large MOA dots like 3 - 6 MOA,

    Unless you can get some 5 shot strings with small group size, I am not sure what to recommend yet.
     
  4. JonM

    JonM Moderator

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    zero it at 100 and then check your 30 and 60. i think you will be pleased doing it that way. when your at very close range your moving the adjusters a lot to get very little movement in impact so as you move to different ranges your finding drasic shifts.

    mechanically zero the dot sight then zero at 100.
     
  5. larich29

    larich29 New Member

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    I zeroed it in at 100 and it still shoots 6 inches low at 30. Oh well. I hope the coyote or deer come out at 100. Lol
     
  6. Triumphman

    Triumphman Active Member

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    Since most AR's are set up with using a High Sight Mount, due to most setting them for 1/3 or Total Witness for the Irons, the closer you get to a Target after Zeroing in at 100yds, the MORE you need to drop the Barrel of the Rifle down, to keep the Scope/Red Dot on Target. Just the nature of way it's set up, and how the Rear Shoulder Stock is made. It's more in a straight alignment to Barrel, than how a Hunting Rifle's Stock is made with it's Drop Heel/Cheek Weld and using Low/Medium type Scope Mounts to keep Scope as close to Bore as possible, that most AR's won't/can't/don't allow.

    If you look at an AR set up for Hunting, it won't have a Tactical/Military style Handguard, but will have a style of Free Float Handguard, where the Rails(receiver/barrel) align, so the Scope Mounts will attach properly to keep Scope away from Shooter's Eye, and kept down low. Mossberg has the MVP(?) and Remington has the R15 I believe. They also have SS Barrels that are around 20" to 24". I'm unsure of Shoulder Stock, but I believe they are a Solid and not an Adjustable. It's been a while since I've looked at one.

    Del
     
  7. JonM

    JonM Moderator

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    if you measure from the center of the rds to the center of the bore its prolly about six inches or pretty close. most of the varience is the height above bore. then add in the adjustment for the drop to 100 and thats where it is supposed to be.

    30 yards aim 6" high, 40 5", 50 4", 60 3", 70 2" 80 1" 90/100 spot on.

    just confirm your drops as my numbers arent exact and i dont know how your rds is zeroed.

    scopes arent much different.