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Big difference in POI

Discussion in 'Black Rifle Forum' started by TEXGLK22, Jan 6, 2011.


  1. TEXGLK22

    TEXGLK22
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    I have a relatively new Reminton VTR carbine. This is my first AR platform rifle and first in .223. I have noticed that when it is zeroed at 100 yards with FMJ, it shoots 4 inches high and 1.5 inches to the left when I switch to soft points or other "premium" expanding type bullets. Is this normal and if so how do you practice using the more affordable fmj's ?


    Thanks in advance,

    TEX
     

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  2. cowboy1964

    cowboy1964
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    What weight is the "premium" ammo that is off so much and what is your barrel twist? Any indication of keyholing on the paper?
     

    #2 cowboy1964, Jan 6, 2011
    Last edited: Jan 6, 2011
  3. Novocaine

    Novocaine
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    My Noveske starts printing 4-6 inches higher when switching from Remington to Fiocchi (both 55gr budget FMJ).
     
  4. B.Reid

    B.Reid
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    I generally buy ammo by the case sight in and shoot the case. Open new case sight in if needed and shoot that case.
     
  5. Scott30

    Scott30
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    Ammo will sight in differently from manufacturer to manufacturer even for the same bullet weight. Differences in powder, crimp, overall length, etc all come into play in accuracy. POI will also vary by lot number from the same manufacturer. The only way to get consistent POI is to reload your own.
     
  6. TEXGLK22

    TEXGLK22
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    The fmjs are Remington UMC with metal case bullets in 55gr. as well as federal 55gr. FMJ

    The others are Remington soft points also in 55gr. Hornady TAP also shoots to the same POI as the soft points.

    1:9 twist with no signs of keyholes. It shoots good groups with all of it, just to different POI.
     
  7. Gunnut 45/454

    Gunnut 45/454
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    TEXGLK22
    Your POI change is do to the difference in velocity (Barrel Harmonics) Even with the same grain bullet! They leave the barrel at different point in the vibration deviation!
    I wouldn't think you'd get that much deviation - is it s thin barrel or heavy barrel? Could your barrel be loose? Or your optic=sights? Is this shooting from a rest or off hand?:whistling:

    I usually don't see that much deviation even when shooting heavy bullets -normally maybe an inch or so up down or side to side at 100 yards!:supergrin:
     
  8. TEXGLK22

    TEXGLK22
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    Gunnut,

    That is what is crazy to me. Nothing is loose and my FIL has the same rifle that shows the same difference in POI. I did not expect that big of a difference. All shooting I am describing is from a rest. To answer your other questoin, the barrel is in the neighborhood of 0.68" and 18".

    TEX
     
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