Ballistic Calculator instead of Chronograph

Discussion in 'Reloading' started by Jinx-), Jul 5, 2011.

  1. Jinx-)

    Jinx-) Well-Known Member

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    Chronograph is a tool anyone working on load development should use, but what if you sighted in @ 100 then fire a group @ 300 and measure bullet drop, knowing bullet drop you can plug data in ballistic calculator and work your muzzle speed till you get same drop. Pocket ballistic calculator reduces stuff you need to carry on your range trip, then get everything setup and try not to loose or break things.
    What do you think?
     
  2. justgoto

    justgoto Well-Known Member

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    I guess that would work... but I use my chronograph to see my ES; that's the only reason I bought it, that is really the only reason I'll use it.

    It is nice to know the exactly speed of my load, but since I am going to find the actual POIs for the distances I shoot at; I only need the estimation from my loading manual.
     

  3. Greyfox

    Greyfox Well-Known Member

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    I have been playing around with this and found that it can be very accurate. The longer the range, the more closely the velocities match. I tried it using impact info at 200, 300, and 500 yards using Ballistic FTE on my I Phone then took the data from my Chrony. Velocities were within 25 FPS. Can't get spread data without the chronograph but group size should correlate and that's really what I'm concerned with.I expect though you could see less similarity with different barrels. With all that I'd still check my impact point at the max range I shoot.
     
  4. Mikecr

    Mikecr Well-Known Member

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    Jinx, everyone has to validate distant target results.
    But using this info to estimate MV is the least accurate approach.

    The chrono provides MV, and distant target drops provide BC adjustment.
     
  5. J E Custom

    J E Custom Well-Known Member

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    It will get you close but will not be exact.

    One is actual, and the other is calculated and there is the difference.

    The best way(Most accurate) is to chronograph at the muzzle and at 100,200 and 300yards.

    At this point you have a very good idea of the Actual BC of the bullet And the velocity at those
    distances.

    From there the Calculated velocities will be very close at longer distances.

    The chronograph also gives lots of other data that the ballistic calculator cannot, so one can't
    replace the other.

    It is an amazing tool but you still need a chronograph in my opinion.

    J E CUSTOM
     
  6. Jinx-)

    Jinx-) Well-Known Member

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    " The chronograph also gives lots of other data that the ballistic calculator cannot, so one can't replace the other. "

    I see thanks, I guess I would have to carry both :D
     
  7. J E Custom

    J E Custom Well-Known Member

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    Now that's is funny .

    I hadn't though about carrying a chroney hunting.

    It will prepare you for that once in a lifetime shot though,before it presents it's self.

    What is the saying ? trash in trash out. I like the one that go's Good data in good data out.

    J E CUSTOM
     
  8. jerrschmitt

    jerrschmitt Well-Known Member

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    I have often wondered about the accuracy of chronographs but I have never seen it addressed.

    From a purely practical point, you may be on to something. If I take a guesstamate of my velocity, use the factory published BC and plug those into a ballistic program then generate a dope card which I fine tune on the range out to 600 yards, by adjusting the velocity and BC figures, do I really need a chronograph? I have never found a load that worked 100% on any ballistic program. I've always had to make adjustments to Velocity or/and BC.

    I know that when I'm done, the prairie dogs are in big trouble.
     
  9. Mikecr

    Mikecr Well-Known Member

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    Yeah right,, is this a GEICO commercial?
    Do chronograph issues exist??

    Do woodchucks chuck wood?
    Was Abraham Lincoln honest?
    Did the little piggy really cry wee wee wee all the way home?

    Ok, sorry
     
  10. J E Custom

    J E Custom Well-Known Member

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    I can only say this about chronographs. You get what you pay for.

    There are always times that they may give you trouble because of light and proximity
    to the muzzle, But these things can be over come with ease.

    Any instrument that samples 4 million times a second should be very accurate. (Some sample
    less per/sec).

    When you can measure 1 ft/sec difference between shots that have a velocity of over 4400 ft/sec
    (My fastest cartrige) I would have to say they are indeed accurate.

    Bullet makers have a habit of claiming higher BCs than actual. The chronograph can verify
    the actual BC by comparing the velocity to the actual trajectory.

    Once this is established your Ballistic calculator can be astonishingly accurate.

    Without good data It is just a guessing game. I am sure it can be done ,But it seems like it is
    subject to error and inconsistent.

    I use my Chronograph for lots of other things beside velocity and find if invaluable. It has saved
    lots of time and money developing loads and comparing pressure effects.

    I could not and would not do without my chronograph.

    Just my opinion.

    J E CUSTOM
     
  11. Trickymissfit

    Trickymissfit Well-Known Member

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    this will work well as long as you are shooting dead level with the curvature of the Earth. An uphill or down hill shot will ruin the equation
    gary
     
  12. Jinx-)

    Jinx-) Well-Known Member

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    I just got back from the range where I was testing my loads for 270 WIN, according to ballistic calculator 130 gr SGK with 61 gr of H4831SC should have +-3100 fps, I was dead on at 300 yards, also I had a friend he got his chrono out, that thing measured 2250 fps, there was another guy shooting flintlock and guess what, those lead balls were flying 4000 fps. With chrono like this I would stick to calculator :D
     
  13. Mikecr

    Mikecr Well-Known Member

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    Well before moon-walking around like your all that, you might see how 'dead on' you are at 200, 400, 500, etc
    I think you'll find that guessing 2 different parameters -at the same time,, isn't the best way to get both of them right..
     
  14. phorwath

    phorwath Well-Known Member

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    Here's a link to a Thread that provides several sets of chronograph data which demonstrate that chronographs are capable of producing consistent, reliable, and credible data. I'll be adding another set of data to this thread - perhaps later today. This latest data set was collected at 985 yards, and was used to establish the BC of a custom bullet manufactured by one of our own - 'elkaholic'.

    http://www.longrangehunting.com/forums/f19/new-oehler-35p-new-skyscreen-rail-first-test-data-60778/