odd question for the long range shooter

Discussion in 'General Rifle Discussion' started by Nathantc, Apr 21, 2013.

  1. Nathantc

    Nathantc New Member

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    ok here goes

    heavier bullets hold there velocity better right

    so two bullets of major weight differences traveling at the same speed at the muzzle should have very similar trajectories when zeroed at 100 yards and then shot at 50 and 150 yards

    basicly lets take a 9mm carbine and a .22lr rifle

    they both start out right at about 1200fps
    the 9mm is 124g
    the .22lr is 36g

    from what i have been reading that would tell me that the heavy 9mm would have a flatter trajectory then the .22lr if shooting out to 200 yards max

    or is there something im missing
     
  2. Salvo

    Salvo New Member

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    The shape of the bullet.

    The information you are thinking of assumes that rifle bullets of similar shape are being compared.
     

  3. Nathantc

    Nathantc New Member

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    that correct,, like .22lr and 9mm are both shaped similar

    lets say if you pushed a .270 110g at the same speed as a 30,06 180g

    same speed now,, same shape, big difference in weight wouldnt the 180g be flatter out to 200 with a 100 yard zero

    i know there is much much more to take in to effect at greater distances
     
  4. c3shooter

    c3shooter Administrator Staff Member

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    Search the term "ballistic coefficent". That is a measure of how well a bullet moves thru air. It is a function of the oversall shape of the bullet, and the diameter of the bullet. A round ball has about the WORST, a long boat tailed spitzer the best.

    Round that have a poor BC will slow down sooner than a round with a good BC. That is, two rounds may START at the same speed, one will slow down before the other. Traveling slower, it will drop more in the time it takes to cross a given distance.

    If we were shooting in a vacuum, it would not matter. This is why so many of the LONG range shooters use 6mm, or 6.6. They have a GREAT BC. For hunting- 25-06 or .270- about as good as it gets.


    http://en.wikipedia.org/wiki/Ballistic_coefficient
     
  5. trip286

    trip286 New Member

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    The effect of gravity is the same for every object. 32 feet per second per second or something like that. Meaning, everything falls to the ground at the same rate of speed (assuming a vacuum).

    Now, where you get differing rates of bullet drop is this... How long the bullet is in the air before hitting its target. That's where BC and velocity come into play. High velocity and low BC will shoot flatter every time, regardless of bullet weight. If a bullet starts out at a higher speed, and loses its velocity more slowly, it will travel to its target quicker, not allowing gravity to affect it as much.

    Now, there may be some that are more susceptible to wind drift, because wind CAN push around lighter bullets easier.
     
  6. Salvo

    Salvo New Member

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    Take a look at a 9mm bullet, and a bullet pulled from a .22lr...

    In any pursuit of truth or fact, the ability and willingness to discriminate is job #1.

    ( Their shapes are quite different. )
     
    Last edited: Apr 22, 2013
  7. Nathantc

    Nathantc New Member

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    ok so then it would be safe to assume that if i go out and get a 9mm carbine it would shoot flatter out to 100 and 200 yards than my .22

    the reason i am looking in to this is im trying to keep my ammo cost as low as i can while sill being able to rid my property of feral dogs and coyotes

    the .22 works but not well,, and my .270win works great but at almost $2 per round and a major problem with over penetration

    some keep telling me to get a .22mag or .17hmr but both will have the same issue i am having with the .22lr,,, just not enough kill power to be blunt

    any way short question,, the 9mm should in theory shoot flatter
     
  8. trip286

    trip286 New Member

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    If it leaves at a higher velocity and has a lower BC, then yes. I personally don't know if it meets either condition.

    I'm trying to dig it up for you, but I can only find ballistics info on 9mm for handguns, not carbines. :(
     
    Last edited: Apr 22, 2013
  9. Nathantc

    Nathantc New Member

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    no ideal what the BC is for the 9mm but i personally chronographed the cheap PMC JHP 124g 9mm from my last hipoint 995ts (16" barrel) right under 1400fps,, cant remember the exact numbers and i know the 22lr is rated at 1250fps,,, i know these numbers wont be exact but there damn close (within 100fps for sure)
     
  10. trip286

    trip286 New Member

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    Then I would consider it sufficient.
     
  11. primer1

    primer1 Well-Known Member Supporter

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    Try to find some low recoil .270s, of find someone to handload some for you. I would think a lighter 130 grain at a slower velocity would be plenty for dogs. BTW, I just saw .270s at wally world for $19 a box.
     
  12. Nathantc

    Nathantc New Member

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    when i said less than $1 per round i didnt mean by a fraction of a penny, its 14-17 per box of 50 and 20-25 per box of 100 of 9mm Remington JHP value pack at wal-mart,,, and i buy firearms in a common cal. cause i dont have the patients for reloading

    one more thing,, there is no low recoil .270win ammo available in stores lol not even the rare 110g has a low recoil
    .270 lets it know your there but not so much in my 18lb custom rig still the 9mm carbine (if flat enough out to 200 yards) just seems to fit the bill much better,, light, no recoil, and cheap ammo that can be had any where. i could just use my SAR-1 for that matter but believe it or not the 7.62x39 round is to much for the task at hand,, it over penetrates just as bad