Where's the barrel pointing at primer impact?

Discussion in 'Rifles, Bullets, Barrels & Ballistics' started by Bart B, Oct 26, 2011.

  1. Bart B

    Bart B Well-Known Member

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    30 caliber bullet from a magnum drops 1.5 inches at 100 yards from horizontal bore axis.

    Scope height above bore axis is 1.5 inches.

    Stock drop at comb is .5 inch below bore axis.

    Stock drop at heel is 1.5 inch below bore axis.

    Rifle's zeroed to strike point of aim at 100 yards from the standing (offhand) position.

    Where's the barrel pointing relative to the aiming point where the scope's reticule's on at primer impact from the firing pin?
     
  2. Nimrodmar10

    Nimrodmar10 Well-Known Member

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    If your bullet drops 1 inch at 100 yards then the barrel is pointed one inch above point of impact. If it drops 50 inches at 500 yards then your barrel is pointed 50 inches above point of impact.
     

  3. davewilson

    davewilson Well-Known Member

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    the barrel is pointing 1.5" above reticle at 100 yards.
     
  4. Loner

    Loner Well-Known Member

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    "off hand" Anywhere from 4 to 8 inches from the aiming point for a decent shooter,
    a lot worse than that for average shooters. I assume this is a trick question.
     
  5. Bart B

    Bart B Well-Known Member

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    I'll interpret this to mean the barrel's pointed 1.5 inches above point of impact (or aiming point).

    It's not a trick question. I'm just trying to find out where folks think the barrel's pointed relative to the target when the round starts firing.
     
    Last edited: Oct 28, 2011
  6. Loner

    Loner Well-Known Member

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    Since point blank range on the round should be way out I would have to say the same.
    If it has a 1.5 drop to the target and is still on it's way up it has to be pointing very close
    to the drop above the target.
     
  7. Bart B

    Bart B Well-Known Member

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    Here's something for readers to think about.

    Handgun front sights' are higher above their bore axis than their rear sights; this is for square notch rear and post front sights.

    Side by side double rifles' bore axes cross at 15 to 30 yards to center both barrels' groups at the point of aim at 50 to 60 yards. The greater calibers and harder kickers' barrel axis cross closer.

    The recoil axis in the rifle stated is a few inches above where its stock rests against the shooter.
     
  8. Coyboy

    Coyboy Well-Known Member

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    Bart is trying to get across the point that it is not an absolute, that recoil may affect the actual point of impact relative to where the barrel is actually pointing.

    For a 22lr that weights 20 lbs and a drop from line of sight of lets say 5" at 100 yards, the barrel most likly is pointing 5" high at 100 yards relative to the aiming point on the target.

    For a 416 hoochie banger, at 8 lbs, the barrel may actually be pointing at or below the line of sight at 100 yards, due to the slightest amount of muzzle jump or flip as the bullet exits the barrel.

    The pistol analagy he used was meant to bring this point to light.

    This is also part of the reason different shooters with the same gun hit in different locations.
     
  9. Mikecr

    Mikecr Well-Known Member

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    Therefore there is no answer.
    It's merely an abstract, and without a clear objective..
     
  10. Coyboy

    Coyboy Well-Known Member

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    pretty much sums it up.
    I wonder if that is the answer Bart is looking for?
     
  11. Bart B

    Bart B Well-Known Member

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    This very well sums it up.

    Note your 416 hoochie banger's bore axis does point below the point above the designated bullet striking point when the firing pin smacks the primer, but that axis moves up as the rifle recoils while the bullet goes down the barrel. Same thing with double rifles; as the bullet goes down the left barrel's bore, that barrel's axis swings both left and up before the bullet exits.

    All I wanted to do was get folks to think about what really happens to the bore axis when a round's fired.