Horizantal spread

Discussion in 'Rifles, Bullets, Barrels & Ballistics' started by Lyons7STW, Sep 12, 2011.

  1. Lyons7STW

    Lyons7STW Well-Known Member

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    what are the causes of hotizantal spread in a group?
    I am currently getting an inch and a half, three shot group at 200 yard
     
  2. Kevin Thomas

    Kevin Thomas Well-Known Member

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    Sounds like a wind issue, but would need a bit more information to say for sure. How many groups fired, and was this consistent in all of them?
     

  3. Lyons7STW

    Lyons7STW Well-Known Member

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    Two identical groups, wind should not have been a factor, like two miles an hour or less. Using 168 berger 7mm @ 3025 fps.
     
  4. Kevin Thomas

    Kevin Thomas Well-Known Member

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    How are you gaging the wind?
     
  5. Lyons7STW

    Lyons7STW Well-Known Member

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    The batteries on my meter were dead so it was an educared guess from experience
     
  6. Kevin Thomas

    Kevin Thomas Well-Known Member

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    Very few anemometers will read down to 1-2 mph reliably, but it must have been absolute calm, I'm assuming. Usually you can't even feel much of anything at these speeds. With this calm of condition, and only six shots fired, I'd say you need to do some more shooting before calling this a legitimate "horizontal spread" rather than just a fluke. Most shooters don't expend anywhere near enough ammo for their groups to be statisically valid, so it really is just an educated guess. Load up some more of the same and repeat the strings at least five times. The horizontal componenet may or may not show up with the increased groups, and that should tell you a bit more.
     
  7. Lyons7STW

    Lyons7STW Well-Known Member

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    Yeah I ran out of day light. I'll shoot some more and see. Thanks
     
  8. jmsbigsmooth

    jmsbigsmooth Well-Known Member

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    Not trying to be rude but usually is caused by the shooter. I struggle with this at times myself. Theres alot of factors involved.
     
  9. Lyons7STW

    Lyons7STW Well-Known Member

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    No offense taken. To rule out my own shooter error I had my uncle shoot it as well. He is an accomplished marksman. The result was the same.
     
  10. Browninglover1

    Browninglover1 Well-Known Member

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    I've found that in my lighter rifles, how I hold the rifle and how it rests on the bags can cause a lot of horizontal spread. The biggest factor in horizontal spread for my shooting is usually the parallax adjustment. If your parallax isn't adjusted right you could easily be getting up to 3 inches of spread in your groups at 200 yards just by the differences in where you place your face on the rifle every time.
     
  11. Lyons7STW

    Lyons7STW Well-Known Member

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    If you were gonna rank suspected factors how would it go. Lets say most likely to least.
    Does stock binding or bedding strike anyone as likely?
     
  12. Lyons7STW

    Lyons7STW Well-Known Member

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    Thank you browning. That makes sense. And was the type of answer i was looking for. It is in fact a lighter rifle. Shooting from bipod and rear bag.

    Rem. 700 LA with standard factory contour barrel in a bell and carlson mountain stock. Gentry break, timney trigger and Leupold vx2 6-18 with target turrets mointed in Leupold rings and base. I will be carrying it in the mountsins a lot.
     
  13. Browninglover1

    Browninglover1 Well-Known Member

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    I'm assuming that particular scope has the Adjustable Objective and using that correctly will make a HUGE difference. Forget the little yardage lines they have marked on it because they are usually not right. Set your gun up so that it will stay on target without you holding it and look through the scope without your head touching the stock. Move your eye up and down and side to side (again try not to hit the stock with your face) and you will see the crosshairs move all over the target. Start twisting the adjustable objective until the point that the crosshairs don't seem to move around the target as you move your eye to different positions. This will eliminate your parallax error and should tighten up your groups a lot.

    The first time I adjusted my parallax correctly I went from 3.5 inches of horizontal spread at 300 yards to .5 inches of horizontal spread on the very next group. If you have exactly (almost impossible) the same eye position on each and every shot the parallax adjustment wouldn't be necessary but since we tend to move our eye to a new position on every shot it seems to dramatically tighten all my groups.

    I do think that bedding could be a factor in your stringing, but I've found more often than not it's usually just a simple parallax error.
     
  14. Lyons7STW

    Lyons7STW Well-Known Member

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    I did assume the paralax adjustment marks were correct. Never had a system like you described for checking it. Your advice seems to coincide with an article carlock wrote on stock fitting, cheek weld and eye/scope alighnment. I am excited to have a specific "factor" to test.