Need help making a drop chart

Discussion in 'Rifles, Bullets, Barrels & Ballistics' started by Too Tall Rosenwald, Dec 11, 2010.

  1. Too Tall Rosenwald

    Too Tall Rosenwald Well-Known Member

    Messages:
    152
    Joined:
    Sep 27, 2009
    Shooting a 180 Berger over 66 grains of H1000, out of a 7WSM.

    OK, so I shoot at 500 yards, come up 5.5 MOA,
    I shoot at 700 yards, come up 9.75 MOA,
    I shoot at 1130 yards, come up 22.5 MOA.

    How do I figure a drop chat, without shooting at every different yards?
     
  2. emmagator

    emmagator Well-Known Member

    Messages:
    315
    Joined:
    Jan 19, 2010
    Go to Vortex Optics - Home and use their long range ballistic calculator.
     

  3. bigngreen

    bigngreen Well-Known Member

    Messages:
    5,841
    Joined:
    Nov 24, 2008
    JBM is very complete way to work it out, and you can print of small drop charts. I make the small cards to back up my ballistics programs so I just tweak the drops to match.

    Also try the program that is in the tool bar on this site, it's the same as the Vortex one, not bad either!
     
  4. Eaglet

    Eaglet Well-Known Member

    Messages:
    2,779
    Joined:
    Feb 2, 2005
    Is your Zero at 200 yards?
    What's the Altitude where you're shooting at?
    Do you remember about what the temperature was?
    Do you know your scope height? ... Distance from center of bore to center of scope.

    Any info like that would help... :)
     
  5. BryanLitz

    BryanLitz <b>Official LRH Sponsor</b>

    Messages:
    633
    Joined:
    Mar 8, 2007
    I briefly tried matching this data. Even with 2950 fps MV, I needed to use a 250 yard zero and go up in altitude about 7,000 feet to get close.

    I suspect:
    either he's actually at very high altitude,
    or
    scope adjustments are moving a little more than 1:1.

    Here's another simple, free ballistics program that you can save on your computer and run trajectory tables with:
    Berger Bullets

    -Bryan
     
  6. Too Tall Rosenwald

    Too Tall Rosenwald Well-Known Member

    Messages:
    152
    Joined:
    Sep 27, 2009
    I got the rifle zeroed at 200. I was about 4000 feet, shooting across the river. It was about 30 degrees or so.
     
  7. BryanLitz

    BryanLitz <b>Official LRH Sponsor</b>

    Messages:
    633
    Joined:
    Mar 8, 2007
    Here's a solution. It doesn't quite match your data. I suspect your scope is adjusting about 15% more than it should. Or possibly you had a vertical wind from shooting over a river.

    Code:
    +----------------------------- Program Inputs ---------------------------------+
    |                                                                              |
    +---- Bullet Inputs -----+----Atmosphere Inputs ----+-------Sight Inputs ------+
    | Caliber: 0.284 inches  | Temperature:  30 degrees | Sight Height: 2.5 inches |
    | Weight: 180 grains     | Pressure: 25.84 inHg     | Zero Range: 200 yards    |
    | G7 BC: 0.337 lb/in^2   | Humidity:  50 %          | Look Angle:   0 degrees  |
    | G7 Form Factor: 0.946  | Density: 0.06988 lb/ft^3 |                          |
    | MZL Velocity:  3000 fps| Wind Speed: 10 mph       |                          |
    |                        | Wind Direction: 3 O'clock|                          |
    +------------------------+--------------------------+--------------------------+
    
    
    +----------------------------- Program Output ---------------------------------+
           Range    Velocity    Energy     Trajectory         TOF          Drift
          (yards)     (fps)     (ft-lb)        (MOA)         (sec)          (MOA)
              0      3000        3597           0.00         0.0000         0.00
             10      2987        3566         -18.96         0.0100        -0.04
             20      2974        3535          -7.20         0.0201        -0.07
             30      2961        3504          -3.41         0.0302        -0.11
             40      2948        3474          -1.61         0.0403        -0.15
             50      2935        3444          -0.60         0.0505        -0.19
             60      2923        3414           0.00         0.0608        -0.22
             70      2910        3384           0.38         0.0711        -0.26
             80      2897        3354           0.61         0.0814        -0.30
             90      2884        3324           0.75         0.0918        -0.34
            100      2871        3295           0.82         0.1022        -0.37
            110      2859        3266           0.84         0.1127        -0.41
            120      2846        3237           0.82         0.1232        -0.45
            130      2833        3208           0.78         0.1338        -0.49
            140      2821        3179           0.71         0.1444        -0.53
            150      2808        3151           0.62         0.1550        -0.57
            160      2795        3123           0.52         0.1657        -0.61
            170      2783        3095           0.41         0.1765        -0.65
            180      2770        3067           0.28         0.1873        -0.68
            190      2758        3039           0.14         0.1981        -0.72
            200      2745        3012          -0.00         0.2090        -0.76
            210      2733        2984          -0.15         0.2200        -0.80
            220      2720        2957          -0.31         0.2310        -0.84
            230      2708        2930          -0.47         0.2420        -0.88
            240      2695        2904          -0.64         0.2531        -0.93
            250      2683        2877          -0.81         0.2643        -0.97
            260      2671        2851          -0.99         0.2755        -1.01
            270      2658        2824          -1.17         0.2868        -1.05
            280      2646        2798          -1.36         0.2981        -1.09
            290      2634        2772          -1.55         0.3094        -1.13
            300      2622        2747          -1.74         0.3209        -1.17
            310      2609        2721          -1.94         0.3323        -1.21
            320      2597        2696          -2.14         0.3438        -1.26
            330      2585        2671          -2.34         0.3554        -1.30
            340      2573        2646          -2.54         0.3671        -1.34
            350      2561        2621          -2.75         0.3787        -1.38
            360      2549        2597          -2.96         0.3905        -1.43
            370      2537        2572          -3.17         0.4023        -1.47
            380      2525        2548          -3.39         0.4141        -1.51
            390      2513        2524          -3.60         0.4260        -1.56
            400      2501        2500          -3.82         0.4380        -1.60
            410      2489        2476          -4.04         0.4500        -1.65
            420      2477        2453          -4.27         0.4621        -1.69
            430      2466        2430          -4.49         0.4742        -1.73
            440      2454        2406          -4.72         0.4864        -1.78
            450      2442        2383          -4.95         0.4987        -1.82
            460      2430        2361          -5.18         0.5110        -1.87
            470      2419        2338          -5.42         0.5234        -1.91
            480      2407        2316          -5.65         0.5358        -1.96
            490      2395        2293          -5.89         0.5483        -2.00
            500      2384        2271          -6.13         0.5608        -2.05
            510      2372        2249          -6.37         0.5735        -2.10
            520      2361        2227          -6.62         0.5861        -2.14
            530      2349        2206          -6.86         0.5989        -2.19
            540      2338        2184          -7.11         0.6117        -2.24
            550      2326        2163          -7.36         0.6245        -2.28
            560      2315        2142          -7.62         0.6375        -2.33
            570      2304        2121          -7.87         0.6504        -2.38
            580      2292        2100          -8.13         0.6635        -2.42
            590      2281        2079          -8.38         0.6766        -2.47
            600      2270        2059          -8.65         0.6898        -2.52
            610      2258        2039          -8.91         0.7030        -2.57
            620      2247        2018          -9.17         0.7164        -2.62
            630      2236        1998          -9.44         0.7297        -2.67
            640      2225        1978          -9.71         0.7432        -2.72
            650      2214        1959          -9.98         0.7567        -2.76
            660      2203        1939         -10.25         0.7703        -2.81
            670      2192        1920         -10.53         0.7839        -2.86
            680      2181        1901         -10.80         0.7977        -2.91
            690      2170        1881         -11.08         0.8115        -2.96
            700      2159        1863         -11.36         0.8253        -3.01
            710      2148        1844         -11.65         0.8392        -3.07
            720      2137        1825         -11.93         0.8532        -3.12
            730      2126        1807         -12.22         0.8673        -3.17
            740      2115        1788         -12.51         0.8815        -3.22
            750      2104        1770         -12.80         0.8957        -3.27
            760      2094        1752         -13.09         0.9100        -3.32
            770      2083        1734         -13.39         0.9243        -3.37
            780      2072        1716         -13.69         0.9388        -3.43
            790      2062        1699         -13.99         0.9533        -3.48
            800      2051        1681         -14.29         0.9679        -3.53
            810      2040        1664         -14.60         0.9825        -3.59
            820      2030        1647         -14.90         0.9973        -3.64
            830      2019        1630         -15.21         1.0121        -3.69
            840      2009        1613         -15.52         1.0270        -3.75
            850      1998        1596         -15.84         1.0420        -3.80
            860      1988        1579         -16.16         1.0570        -3.86
            870      1977        1563         -16.47         1.0722        -3.91
            880      1967        1546         -16.80         1.0874        -3.97
            890      1957        1530         -17.12         1.1027        -4.02
            900      1946        1514         -17.45         1.1180        -4.08
            910      1936        1498         -17.77         1.1335        -4.13
            920      1926        1482         -18.11         1.1490        -4.19
            930      1915        1466         -18.44         1.1646        -4.25
            940      1905        1451         -18.78         1.1803        -4.30
            950      1895        1435         -19.11         1.1961        -4.36
            960      1885        1420         -19.46         1.2120        -4.42
            970      1875        1405         -19.80         1.2280        -4.48
            980      1865        1389         -20.15         1.2440        -4.53
            990      1854        1374         -20.50         1.2601        -4.59
           1000      1844        1360         -20.85         1.2764        -4.65
           1010      1834        1345         -21.20         1.2927        -4.71
           1020      1824        1330         -21.56         1.3091        -4.77
           1030      1814        1316         -21.92         1.3256        -4.83
           1040      1804        1301         -22.28         1.3421        -4.89
           1050      1794        1287         -22.65         1.3588        -4.95
           1060      1784        1273         -23.02         1.3756        -5.01
           1070      1775        1259         -23.39         1.3924        -5.07
           1080      1765        1245         -23.76         1.4094        -5.13
           1090      1755        1231         -24.14         1.4264        -5.19
           1100      1745        1217         -24.52         1.4436        -5.26
           1110      1735        1203         -24.90         1.4608        -5.32
           1120      1726        1190         -25.29         1.4782        -5.38
           1130      1716        1177         -25.68         1.4956        -5.44
     
  8. LouBoyd

    LouBoyd Well-Known Member

    Messages:
    770
    Joined:
    Oct 15, 2007
    "I briefly tried matching this data. Even with 2950 fps MV, I needed to use a 250 yard zero and go up in altitude about 7,000 feet to get close"

    Make sure you enter the value for the sight height above the bore distance accurately into the computer program. Measure the best you can to 0.01" if you can. If that value isn't correct it will screw up all of the drop calculations.
    Think about every input to the program carefully and get them correct
     
  9. wvcountryboy

    wvcountryboy Well-Known Member

    Messages:
    47
    Joined:
    Dec 1, 2010
    Buy the infinity program from sierra. It tells you everything. It tells you the energy and velocity at any yardage you want. I click my scope and that is what i use to determine my clicks.