trajectory help please...

Discussion in 'Rifles, Bullets, Barrels & Ballistics' started by grit, Jan 23, 2006.

  1. grit

    grit Well-Known Member

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    Did some shooting today. I recorded my poi's, to build a data card. I've played with a couple ballistics calculators, and can't quite tweak them to get the same results.

    Rifle: Winchester 70 24" sporter
    caliber: 270 win
    load: 140 grain sst bc-.495
    RL19 56.4
    federal 210
    remington brass
    Mv: unknown

    Come ups required for poa impact:
    500 yards- 8 moa
    600-10.75 moa
    700- 14.25 moa
    800- 18 moa

    Temp: 55 degrees
    Elevation: 4000
    Cant: 5 degrees

    Can someone help me build a card from this info? Why can't I get a match?
     
  2. Tim Behle

    Tim Behle Well-Known Member

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    I'm in the same boat as you. It would be nice if someone would come up with a ballistics program that would allow you to put in actual drops and bullet speeds for each shot, then adjust bullet's BC and create a working drop chart.

    One load I worked up a few days ago, the Point Blank program said that I'd need 16 3/4 MOA to be on target at 800 yards. Turned out I only needed to come up 12 MOA. But it won't let me Input the actual numbers.

    Sometimes I think these Ballistic programs are designed by Dan Lilja. Because by the time I get a barrel figured out, it's shot out and needs to be replaced!
     

  3. CAM

    CAM Well-Known Member

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    grit

    I don't shot a 270 so I could be way off base here.
    with the info you gave, the key is 10MOA between 500 and 800

    Try 2935 Fps with a 150 yard zero

    CAM
     
  4. edge

    edge Well-Known Member

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    What is the height of the sight above the muzzle?

    Are you Zero MOA @ 100 yards?

    Best guess as to MV?

    Adjusted B.C.( 0.570 ) or Sea Level B.C. (0.405 )??

    edge.
     
  5. royinidaho

    royinidaho Writers Guild

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    You entered the realm where I once was. The problem is that I'm still there /ubbthreads/images/graemlins/grin.gif

    Gotta run to work at the moment, will respond later today if some one else doesn't nail it.

    If you have some time and have microsoft excell build a table of you data and graph it. Then generate the equation for the curve. Do whatever gets the best fit. R = 1 for perfect.

    If all of this is jibberish, I'll do one for you and send it.

    You don't have to worry about the unknown velocity. Just so the drop chart works.

    Heck, all you wanna hear is "bonk" /ubbthreads/images/graemlins/grin.gif /ubbthreads/images/graemlins/grin.gif
     
  6. edge

    edge Well-Known Member

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    [ QUOTE ]
    SNIP

    You don't have to worry about the unknown velocity. Just so the drop chart works.

    Heck, all you wanna hear is "bonk" /ubbthreads/images/graemlins/grin.gif /ubbthreads/images/graemlins/grin.gif

    [/ QUOTE ]

    For your needs Roy in Idaho is right.

    If you want to use a program then you either need more info or just play with the numbers.

    I would like a few of the closer drops for back testing your curve.

    edge.
     
  7. Dave King

    Dave King Well-Known Member

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    This is close although it may be of no value. You'd need to check your 100 yard zero and some of the other intermediate ranges.



    Velocity (fps)......3060
    Bullet Weight (gr)..140
    Bullet BC..............0.430
    Start Distance......0
    Range Increment...25
    Altitude (ft)........4000
    Temperature (F)....55
    Scope Height (inch).1.75
    Mil Value (3.44, 3.6).....3.440
    MOA value (1.0, 1.047)..1.047
    Zero Range (yds)........100


    <font class="small">Code:</font><hr /><pre>
    Range Vely Energy Total Bullet MOA Mil
    yds fps ft/lbs Drop Path Drop Drop
    0 3060 2910 0.0 -1.8 0.0 0.00
    25 3010 2816 -0.1 -0.9 -3.6 1.05
    50 2961 2725 -0.5 -0.4 -0.7 0.21
    75 2912 2635 -1.1 -0.1 -0.1 0.02
    100 2864 2549 -1.9 0.0 0.0 0.00
    125 2817 2466 -3.1 -0.2 -0.1 0.04
    150 2770 2385 -4.5 -0.7 -0.4 0.12
    175 2723 2304 -6.2 -1.5 -0.8 0.23
    200 2677 2227 -8.2 -2.5 -1.2 0.35
    225 2632 2153 -10.4 -3.9 -1.6 0.48
    250 2587 2080 -13.0 -5.5 -2.1 0.61
    275 2542 2008 -16.0 -7.5 -2.6 0.76
    300 2498 1939 -19.2 -9.8 -3.1 0.91
    325 2454 1871 -22.8 -12.5 -3.7 1.07
    350 2411 1806 -26.7 -15.5 -4.2 1.23
    375 2368 1742 -31.0 -18.9 -4.8 1.40
    400 2326 1681 -35.7 -22.7 -5.4 1.58
    425 2284 1621 -40.9 -26.9 -6.1 1.76
    450 2242 1562 -46.5 -31.6 -6.7 1.95
    475 2201 1505 -52.5 -36.7 -7.4 2.15
    500 2161 1451 -58.8 -42.1 -8.0 2.34
    525 2120 1397 -65.9 -48.2 -8.8 2.55
    550 2080 1344 -73.2 -54.7 -9.5 2.76
    575 2041 1294 -81.0 -61.5 -10.2 2.97
    600 2002 1245 -89.2 -68.8 -11.0 3.18
    625 1963 1197 -98.1 -76.7 -11.7 3.41
    650 1925 1151 -107.5 -85.2 -12.5 3.64
    675 1887 1106 -117.5 -94.4 -13.4 3.88
    700 1850 1063 -128.2 -104.1 -14.2 4.13
    725 1813 1021 -139.8 -114.7 -15.1 4.39
    750 1777 981 -151.9 -126.0 -16.0 4.66
    775 1742 943 -164.7 -137.8 -17.0 4.94
    800 1707 905 -178.3 -150.5 -18.0 5.22
    825 1673 870 -192.5 -163.8 -19.0 5.51
    850 1639 835 -207.7 -178.1 -20.0 5.82
    875 1606 801 -223.4 -192.9 -21.1 6.12
    900 1573 769 -240.1 -208.6 -22.1 6.44
    925 1540 737 -257.9 -225.4 -23.3 6.77
    950 1508 706 -276.1 -242.7 -24.4 7.09
    975 1477 678 -294.7 -260.4 -25.5 7.42
    1000 1448 651 -315.5 -280.3 -26.8 7.78

    </pre><hr />
     
  8. royinidaho

    royinidaho Writers Guild

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    Here ya go Grit....

    Here's what you posted:
    [​IMG]

    Here's the drop chart. The numbers track real well with your numbers.

    You have no email address on your bio or I would have sent the spread sheet.

    I keep things pretty simple. When you ground truth the chart you'll be ready to go.

    Keep in mind that it is good for only the elevation, humidity, barometric pressure, up or down angle you were shooting and, the way you were holding your mouth the day you charted the numbers. /ubbthreads/images/graemlins/grin.gif

    Sorry for the smallitity (new word I just invented), kind of hard on the eyes but is the best I can do in the time I had.:(

    Also no quality control applied. Verify all number. Not responsible for any misses you make. Though, will take credit for any hits.;)
    [​IMG]
     
  9. Len Backus

    Len Backus Administrator Staff Member

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    Gosh, this site sure has a helpful bunch of guys.
     
  10. grit

    grit Well-Known Member

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    [ QUOTE ]
    Gosh, this site sure has a helpful bunch of guys.

    [/ QUOTE ]
    Len's right. You guys are fantastic!

    Roy, I updated my profile to include an e mail. Please send me the spreadsheet. mybyky@yahoo.com

    About the bc: The bc I was putting in the program (eskimo.com something, from this forum) is the one listed on the hornady website (what's it based on?). Adjusted bc?? The bc changes with altitude and velocity? How do I figure an accurate bc to plug into the programs?

    Thanks gentlemen!!

    I just realized I made a mistake. Let me clarify a couple things.

    I realized I stated a five degree cant on my initial post. What I meant was I shot at a five degree inclination. What I want to do is get a match on a ballistics program I can save and vary as necessary. I don't know how much difference a five degree inclination makes.
     
  11. James H

    James H Well-Known Member

    Messages:
    504
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    Jan 15, 2006
    Dave KIng

    [ QUOTE ]
    This is close although it may be of no value. You'd need to check your 100 yard zero and some of the other intermediate ranges.



    Velocity (fps)......3060
    Bullet Weight (gr)..140
    Bullet BC..............0.430
    Start Distance......0
    Range Increment...25
    Altitude (ft)........4000
    Temperature (F)....55
    Scope Height (inch).1.75
    Mil Value (3.44, 3.6).....3.440
    MOA value (1.0, 1.047)..1.047
    Zero Range (yds)........100


    <font class="small">Code:</font><hr /><pre>
    Range Vely Energy Total Bullet MOA Mil
    yds fps ft/lbs Drop Path Drop Drop
    0 3060 2910 0.0 -1.8 0.0 0.00
    25 3010 2816 -0.1 -0.9 -3.6 1.05
    50 2961 2725 -0.5 -0.4 -0.7 0.21
    75 2912 2635 -1.1 -0.1 -0.1 0.02
    100 2864 2549 -1.9 0.0 0.0 0.00
    125 2817 2466 -3.1 -0.2 -0.1 0.04
    150 2770 2385 -4.5 -0.7 -0.4 0.12
    175 2723 2304 -6.2 -1.5 -0.8 0.23
    200 2677 2227 -8.2 -2.5 -1.2 0.35
    225 2632 2153 -10.4 -3.9 -1.6 0.48
    250 2587 2080 -13.0 -5.5 -2.1 0.61
    275 2542 2008 -16.0 -7.5 -2.6 0.76
    300 2498 1939 -19.2 -9.8 -3.1 0.91
    325 2454 1871 -22.8 -12.5 -3.7 1.07
    350 2411 1806 -26.7 -15.5 -4.2 1.23
    375 2368 1742 -31.0 -18.9 -4.8 1.40
    400 2326 1681 -35.7 -22.7 -5.4 1.58
    425 2284 1621 -40.9 -26.9 -6.1 1.76
    450 2242 1562 -46.5 -31.6 -6.7 1.95
    475 2201 1505 -52.5 -36.7 -7.4 2.15
    500 2161 1451 -58.8 -42.1 -8.0 2.34
    525 2120 1397 -65.9 -48.2 -8.8 2.55
    550 2080 1344 -73.2 -54.7 -9.5 2.76
    575 2041 1294 -81.0 -61.5 -10.2 2.97
    600 2002 1245 -89.2 -68.8 -11.0 3.18
    625 1963 1197 -98.1 -76.7 -11.7 3.41
    650 1925 1151 -107.5 -85.2 -12.5 3.64
    675 1887 1106 -117.5 -94.4 -13.4 3.88
    700 1850 1063 -128.2 -104.1 -14.2 4.13
    725 1813 1021 -139.8 -114.7 -15.1 4.39
    750 1777 981 -151.9 -126.0 -16.0 4.66
    775 1742 943 -164.7 -137.8 -17.0 4.94
    800 1707 905 -178.3 -150.5 -18.0 5.22
    825 1673 870 -192.5 -163.8 -19.0 5.51
    850 1639 835 -207.7 -178.1 -20.0 5.82
    875 1606 801 -223.4 -192.9 -21.1 6.12
    900 1573 769 -240.1 -208.6 -22.1 6.44
    925 1540 737 -257.9 -225.4 -23.3 6.77
    950 1508 706 -276.1 -242.7 -24.4 7.09
    975 1477 678 -294.7 -260.4 -25.5 7.42
    1000 1448 651 -315.5 -280.3 -26.8 7.78

    </pre><hr />

    [/ QUOTE ]

    Dave do you have a terminal ballistics program that calculates the drop in mils or did you do as I and calculat them from info from your ballistics program.
    If your ballistics program does, what are you using?
     
  12. Dave King

    Dave King Well-Known Member

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  13. royinidaho

    royinidaho Writers Guild

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    Len
    Yep, there are.... But on the other hand /ubbthreads/images/graemlins/grin.gif /ubbthreads/images/graemlins/grin.gif /ubbthreads/images/graemlins/grin.gif

    Grit,
    The program that Dave posted the results from, takes care of changing BC with environmental conditions. You enter all of the info, barometric pressure, temp, etc and it takes it all into account.

    That's why I said that what I posted is good for the conditions under which you shot. Recall I said all you wanted was a "bonk".

    With the program that Dave used, calcuate once, then enter the values for the day you are shooting, whenever it is, and you get a 'bonk' every time.

    Me thinks that Dave gets a 'bonk' about every shot. Unless he forgets which bbl he has screwed on the action. /ubbthreads/images/graemlins/grin.gif

    Regarding you 'cant'.

    Angle is 5 degrees. Cosine of 5 degrees is .996

    1000 yds * .996 = 996 yds. So at 1000 yds you hold for 996 w/a 5 degree up or down angle.

    I'm not into the click thing quite yet, using a mil dot so I just nudge up/down as necessary.

    There's a thing on that eskimo.com site that does all of the above for you.