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Need help sighting in rifle.

Discussion in 'Rifle Discussion' started by flybynyt, Sep 1, 2012.

  1. flybynyt

    flybynyt Battleground, WA Active Member

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    I live close to English Pit, and have never sighted in a rifle before. I was wondering if anybody would want to meet me there and help?
    I have an AR-15 with a Reticle Red Dot Open Reflex Sight .

    Thanks
     
  2. Skang

    Skang WA Well-Known Member

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    staff at english pit can help you.

    however, it's very very simple. Watch you-tube videos. I mean it, very simple.

    Key is bench rest and steady trigger pull.

    I do live close by English pit, but I never been there. ;)
     
  3. Gaust

    Gaust Portland Member

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    Do you have iron sights that are sighted in?
     
  4. flybynyt

    flybynyt Battleground, WA Active Member

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    Only the sights it came with. I'm sure I can figure it out. I'll check out some YouTube videos.
    I wasn't sure how complicated it was with a red dot type sight. Thanks for the input.

    ar15.jpg


    reddot.jpg
     
  5. Skang

    Skang WA Well-Known Member

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  6. mjbskwim

    mjbskwim Salmon,Idaho Well-Known Member

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    The AR is pretty easy to sight in, since the trajectory of the round makes sighting in at 27? yards the same as 100 yards.

    So take the upper off.
    Put it in a vice and look down the barrel to line it up with something at 27 yards away.
    Then making sure not to move the upper,adjust the sight to hit the same spot.
    That should get you on paper

    Then take a shot (after you put the gun back together,lol)
    Now keeping the gun as stationary as possible,adjust the site to match the bullet hole (there is a you tube video on this,BTW. Sighting in with 2 shots? I believe)
    Shoot again and you should be right on.

    The first part works with a bolt gun also.Just remove the bolt.
    And it can be done on a semi auto with a very small mirror.(gun smith taught me that one)
     
  7. the4thshake

    the4thshake Portland Active Member

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    Try sighting in at 50 yards. That should put you around an inch high at 100 yards and about dead on at 200. A 27 yard zero will leave you almost 6 inches high at 100 yards.

    The above method of looking down the barrel with the bolt carrier removed should get you pretty close. Propping the upper up with sand bags helps.
     
  8. mjbskwim

    mjbskwim Salmon,Idaho Well-Known Member

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    Well most of the ballistic people say the bullet is at the same plane at 27yds,for a 223/556,as it is at 100.
    But that's just what some smart guy put there for me to read.
    Get that? The bullet,on it's little rise,at 27 yards,will be at the same plane,in your line of sight,when it starts to fall,at 100.
    So sighting it in at 27 yards should put you dead on at 100,not 6 inches high.
    As long as you are shooting flat and not at a downward angle.

    I have a deer to finish
     
  9. the4thshake

    the4thshake Portland Active Member

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    Lets see what the "ballistic people" say......


    +----------------------------- Program Inputs ---------------------------------+
    | |
    +---- Bullet Inputs -----+----Atmosphere Inputs ----+-------Sight Inputs ------+
    | Caliber: 0.224 inches | Temperature: 59 degrees | Sight Height: 2.6 inches |
    | Weight: 55 grains | Pressure: 29.92 inHg | Zero Range: 27 yards |
    | G7 BC: 0.243 lb/in^2 | Humidity: 0 % | Look Angle: 0 degrees |
    | G7 Form Factor: 0.644 | Density: 0.07647 lb/ft^3 | |
    | MZL Velocity: 3050 fps| Wind Speed: 10 mph | |
    | | Wind Direction: 3 O'clock| |
    +------------------------+--------------------------+--------------------------+


    +----------------------------- Program Output ---------------------------------+
    Range Velocity Energy Trajectory TOF Drift
    (yards) (fps) (ft-lb) (inches) (sec) (inches)
    0 3050 1136 -2.60 0.0000 0.00
    25 3000 1099 -0.18 0.0248 -0.04
    50 2950 1063 1.99 0.0500 -0.15
    75 2900 1027 3.92 0.0756 -0.33
    100 2851 993 5.59 0.1017 -0.60
    125 2802 959 6.99 0.1283 -0.94
    150 2754 926 8.11 0.1553 -1.36
    175 2706 894 8.95 0.1827 -1.87
    200 2658 863 9.49 0.2107 -2.47
    225 2611 833 9.72 0.2391 -3.15
    250 2565 803 9.64 0.2681 -3.92
    275 2519 775 9.22 0.2976 -4.79
    300 2473 747 8.47 0.3277 -5.75


    5.59 is pretty close to 6 now isn't it?

    It's still "on it's little rise" out to 225 yards.


    Get that?
     
  10. Skang

    Skang WA Well-Known Member

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    It doesn't matter what the bullet graph/chart said. It will get you close, but you always have shoot to confirm.
     
  11. civilian75

    civilian75 Hillsboro, OR Well-Known Member

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    OP,

    For me, rifle sighting starts at home. I separate the upper and remove the BCG. I secure the upper to a solid platform. While looking thru the barrel from the chamber side, I align the barrel at a target at 35yds (measure as accurately as possible), then, I adjust the sights to aim at same target.

    At the range, adjust your sight at 0.5" over point of aim at 50 yds, that will give you a zero at ~200 yd and a very flat trajectory, to higher than 2" at 110 - 120 yds. Then sight your rifle at 100yd. POI should be ~1.5" POA. Then take it to the 200yd range to do finalize the fine tuning. Should work for both M855 and M193.

    EDIT: The numbers above assume a bore centerline to line of sight distance of 1.5". Your M4 with carry handle or red dot probably is 2.5", maybe as much as 3", can't say for sure. The near point blank zero will be at 60 yds or 70yd, respectively, not 35yd as I indicated above. Sorry for the mistake. That said, at 50yds, bullets will hit ~3/4" below point of aim. At 100yd, about ~3/4" over POA.
     
  12. the4thshake

    the4thshake Portland Active Member

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    Look again at the sight height on the chart. 2.6