Ghost
8 Point Buck
"Friendship must never be buried under the weight of misunderstanding."
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Post by Ghost on Oct 23, 2009 3:18:28 GMT -5
I have been beating my brain over this one and I can not get my head around this issue. I understand the concept of the BC (Ballistic Coefficient) and have a decent understanding of a few of the drag models. But, according to my readings the G1 drag model is the basic drag model used by manufacturers today and is sometimes used to pad the bullets BC of the mfg making them look better than what they really are. That being said, I am also under the impression that the G1 is best used for ranges under 500 yards and is based off of flat based, pointed bullets. Okay, with me so far?
Now to the hard part, for me anyway.
The G7 which to my understanding is a better and more accurate drag model for longer range, i.e greater than 500 yards. I understand that the G7 is used for VLD or pointed boat tails which is the bullet type I am running.
Before we go any further I need to llet you know what program I am running (www.jbmballistics.com/) just click on calculations and look for Trajectory simplified.
Now back to my problem. The bullet that is currently in question is the Nosler Accu Bond 150 gr .308 WIN. the G1 BC is 0.435. Now if you look at the program that I am using it gives you several options for a drag model in the BC entry, G7 being one of them. If I enter the G1 BC and select from the options, the program does not convert the G1 to the G7 drag model. How does a person convert the given BC ( by the mfg) from the G1 drag model so that it applies to the G7 drag model? From what I am seeing on the net the typical G7 BC is lower that the G1 BC, sometime by several points. It seems the more I try to understand this model the more confused I get. I am really lost on this. I want to understand what this is and how to apply it and I need some help. How do I work the G7 Drag Model?
Thnks for your time.
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Ghost
8 Point Buck
"Friendship must never be buried under the weight of misunderstanding."
Posts: 465
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Joined: May 14, 2024 7:14:03 GMT -5
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Post by Ghost on Oct 23, 2009 7:16:45 GMT -5
correct me if I am wrong, this is a shot in the dark.
Say the MV for the Nosler accubond 150 gr from a .308 with a 26" barrel was 3025. Would it be safe to say, that you would calculate the drag from the velocity? If so by another program I found, the G7 calculates out to be 0.246 BC. Right or wrong? Definitely a substantial drop from 0.435 G1 that the manufacturer states.
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Ghost
8 Point Buck
"Friendship must never be buried under the weight of misunderstanding."
Posts: 465
Likes: 0
Joined: May 14, 2024 7:14:03 GMT -5
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Post by Ghost on Oct 23, 2009 7:33:48 GMT -5
Run this by you and see if this sounds possible.
Same set up
G7 0.256 @ 500 yrds zero
Read the ballistics also compare the MPBR and MPBR Zero with the G1 that will be posted next. Keep in mind this is the G7 Model.
Trajectory (Simplified) Input Data Ballistic Coefficient: 0.246 G7 Caliber: 0.308 in Bullet Weight: 150.0 gr Muzzle Velocity: 3025.0 ft/s Sight Height: 2.00 in Line Of Sight Angle: 0.0 deg Cant Angle: 0.0 deg Wind Speed: 0.0 mph Target Speed: 0.0 mph Temperature: 59.0 °F Pressure: 29.92 in Hg Humidity: 0.0 % Altitude: 0.0 ft Std. Atmosphere at Altitude: No Pressure is Corrected: Yes Zero at Max. Point Blank Range: No Target Relative Drops: Yes Round Output to Whole Numbers: No Output Data Elevation: 11.944 MOA Windage: 0.000 MOA Atmospheric Density: 0.07647 lb/ft³ Speed of Sound: 1116.5 ft/s Maximum PBR: 371 yd Maximum PBR Zero: 316 yd Range of Maximum Height: 177 yd Energy at Maximum PBR: 1811.1 ft•lbs Sectional Density: 0.226 lb/in² Calculated Table Range Drop Drop Windage Windage Velocity Mach Energy Time Lead Lead (yd) (in) (MOA) (in) (MOA) (ft/s) (none) (ft•lbs) (s) (in) (MOA) 10 -0.8 -7.3 0.0 0.0 3005.2 2.692 3007.4 0.010 0.0 0.0 20 0.4 2.0 0.0 0.0 2985.4 2.674 2967.9 0.020 0.0 0.0 30 1.6 5.0 0.0 0.0 2965.6 2.656 2928.8 0.030 0.0 0.0 40 2.7 6.4 0.0 0.0 2946.0 2.639 2890.1 0.040 0.0 0.0 50 3.8 7.2 0.0 0.0 2926.4 2.621 2851.8 0.050 0.0 0.0 60 4.8 7.6 0.0 0.0 2906.8 2.604 2813.8 0.061 0.0 0.0 70 5.8 7.9 0.0 0.0 2887.3 2.586 2776.2 0.071 0.0 0.0 80 6.7 8.1 0.0 0.0 2867.9 2.569 2738.9 0.081 0.0 0.0 90 7.7 8.1 0.0 0.0 2848.5 2.551 2702.1 0.092 0.0 0.0 100 8.5 8.1 0.0 0.0 2829.2 2.534 2665.5 0.103 0.0 0.0 110 9.3 8.1 0.0 0.0 2810.0 2.517 2629.4 0.113 0.0 0.0 120 10.1 8.1 0.0 0.0 2790.8 2.500 2593.6 0.124 0.0 0.0 130 10.9 8.0 0.0 0.0 2771.7 2.483 2558.2 0.135 0.0 0.0 140 11.5 7.9 0.0 0.0 2752.6 2.465 2523.2 0.146 0.0 0.0 150 12.2 7.8 0.0 0.0 2733.6 2.448 2488.5 0.156 0.0 0.0 160 12.8 7.6 0.0 0.0 2714.7 2.432 2454.2 0.167 0.0 0.0 170 13.3 7.5 0.0 0.0 2695.9 2.415 2420.2 0.179 0.0 0.0 180 13.8 7.3 0.0 0.0 2677.1 2.398 2386.6 0.190 0.0 0.0 190 14.3 7.2 0.0 0.0 2658.4 2.381 2353.4 0.201 0.0 0.0 200 14.7 7.0 0.0 0.0 2639.7 2.364 2320.5 0.212 0.0 0.0 210 15.0 6.8 0.0 0.0 2621.2 2.348 2288.0 0.224 0.0 0.0 220 15.4 6.7 0.0 0.0 2602.7 2.331 2255.8 0.235 0.0 0.0 230 15.6 6.5 0.0 0.0 2584.2 2.315 2224.0 0.247 0.0 0.0 240 15.8 6.3 0.0 0.0 2565.9 2.298 2192.5 0.258 0.0 0.0 250 16.0 6.1 0.0 0.0 2547.6 2.282 2161.3 0.270 0.0 0.0 260 16.0 5.9 0.0 0.0 2529.4 2.266 2130.5 0.282 0.0 0.0 270 16.1 5.7 0.0 0.0 2511.2 2.249 2100.1 0.294 0.0 0.0 280 16.1 5.5 0.0 0.0 2493.2 2.233 2069.9 0.306 0.0 0.0 290 16.0 5.3 0.0 0.0 2475.2 2.217 2040.2 0.318 0.0 0.0 300 15.9 5.1 0.0 0.0 2457.2 2.201 2010.7 0.330 0.0 0.0 310 15.7 4.8 0.0 0.0 2439.4 2.185 1981.6 0.342 0.0 0.0 320 15.4 4.6 0.0 0.0 2421.6 2.169 1952.8 0.355 0.0 0.0 330 15.1 4.4 0.0 0.0 2403.9 2.153 1924.4 0.367 0.0 0.0 340 14.8 4.1 0.0 0.0 2386.3 2.137 1896.2 0.380 0.0 0.0 350 14.3 3.9 0.0 0.0 2368.7 2.122 1868.4 0.392 0.0 0.0 360 13.9 3.7 0.0 0.0 2351.2 2.106 1840.9 0.405 0.0 0.0 370 13.3 3.4 0.0 0.0 2333.8 2.090 1813.8 0.418 0.0 0.0 380 12.7 3.2 0.0 0.0 2316.5 2.075 1786.9 0.431 0.0 0.0 390 12.0 2.9 0.0 0.0 2299.2 2.059 1760.4 0.444 0.0 0.0 400 11.3 2.7 0.0 0.0 2282.0 2.044 1734.2 0.457 0.0 0.0 410 10.5 2.4 0.0 0.0 2264.9 2.029 1708.3 0.470 0.0 0.0 420 9.6 2.2 0.0 0.0 2247.9 2.013 1682.7 0.483 0.0 0.0 430 8.6 1.9 0.0 0.0 2230.9 1.998 1657.4 0.497 0.0 0.0 440 7.6 1.7 0.0 0.0 2214.0 1.983 1632.4 0.510 0.0 0.0 450 6.5 1.4 0.0 0.0 2197.2 1.968 1607.7 0.524 0.0 0.0 460 5.4 1.1 0.0 0.0 2180.5 1.953 1583.4 0.538 0.0 0.0 470 4.1 0.8 0.0 0.0 2163.9 1.938 1559.3 0.551 0.0 0.0 480 2.8 0.6 0.0 0.0 2147.3 1.923 1535.5 0.565 0.0 0.0 490 1.5 0.3 0.0 0.0 2130.8 1.909 1512.0 0.579 0.0 0.0 500 -0.0 -0.0 0.0 0.0 2114.4 1.894 1488.8 0.593 0.0 0.0 23/10/09 05:31, JBM/jbmtraj_simp-5.0.cgi
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Ghost
8 Point Buck
"Friendship must never be buried under the weight of misunderstanding."
Posts: 465
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Joined: May 14, 2024 7:14:03 GMT -5
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Post by Ghost on Oct 23, 2009 7:35:26 GMT -5
Same set up but using the G1 Model
Again look at the MPBR and The MPBR Zero.
Trajectory (Simplified) Input Data Ballistic Coefficient: 0.435 G1 Caliber: 0.308 in Bullet Weight: 150.0 gr Muzzle Velocity: 3025.0 ft/s Sight Height: 2.00 in Line Of Sight Angle: 0.0 deg Cant Angle: 0.0 deg Wind Speed: 0.0 mph Target Speed: 0.0 mph Temperature: 59.0 °F Pressure: 29.92 in Hg Humidity: 0.0 % Altitude: 0.0 ft Std. Atmosphere at Altitude: No Pressure is Corrected: Yes Zero at Max. Point Blank Range: No Target Relative Drops: Yes Round Output to Whole Numbers: No Output Data Elevation: 12.371 MOA Windage: 0.000 MOA Atmospheric Density: 0.07647 lb/ft³ Speed of Sound: 1116.5 ft/s Maximum PBR: 365 yd Maximum PBR Zero: 311 yd Range of Maximum Height: 175 yd Energy at Maximum PBR: 1702.7 ft•lbs Sectional Density: 0.226 lb/in² Calculated Table Range Drop Drop Windage Windage Velocity Mach Energy Time Lead Lead (yd) (in) (MOA) (in) (MOA) (ft/s) (none) (ft•lbs) (s) (in) (MOA) 10 -0.7 -6.9 0.0 0.0 3002.2 2.689 3001.5 0.010 0.0 0.0 20 0.5 2.5 0.0 0.0 2979.5 2.669 2956.2 0.020 0.0 0.0 30 1.7 5.5 0.0 0.0 2956.9 2.648 2911.6 0.030 0.0 0.0 40 2.9 6.9 0.0 0.0 2934.4 2.628 2867.5 0.040 0.0 0.0 50 4.0 7.6 0.0 0.0 2912.1 2.608 2824.0 0.051 0.0 0.0 60 5.1 8.1 0.0 0.0 2889.9 2.588 2781.1 0.061 0.0 0.0 70 6.1 8.3 0.0 0.0 2867.8 2.569 2738.7 0.071 0.0 0.0 80 7.1 8.5 0.0 0.0 2845.8 2.549 2696.8 0.082 0.0 0.0 90 8.0 8.5 0.0 0.0 2823.9 2.529 2655.5 0.092 0.0 0.0 100 9.0 8.6 0.0 0.0 2802.1 2.510 2614.7 0.103 0.0 0.0 110 9.8 8.5 0.0 0.0 2780.4 2.490 2574.4 0.114 0.0 0.0 120 10.6 8.5 0.0 0.0 2758.9 2.471 2534.6 0.125 0.0 0.0 130 11.4 8.4 0.0 0.0 2737.4 2.452 2495.4 0.136 0.0 0.0 140 12.1 8.3 0.0 0.0 2716.1 2.433 2456.6 0.147 0.0 0.0 150 12.8 8.2 0.0 0.0 2694.8 2.414 2418.3 0.158 0.0 0.0 160 13.4 8.0 0.0 0.0 2673.7 2.395 2380.5 0.169 0.0 0.0 170 14.0 7.9 0.0 0.0 2652.6 2.376 2343.2 0.180 0.0 0.0 180 14.6 7.7 0.0 0.0 2631.7 2.357 2306.3 0.191 0.0 0.0 190 15.0 7.6 0.0 0.0 2610.8 2.338 2269.9 0.203 0.0 0.0 200 15.5 7.4 0.0 0.0 2590.1 2.320 2234.0 0.214 0.0 0.0 210 15.9 7.2 0.0 0.0 2569.4 2.301 2198.5 0.226 0.0 0.0 220 16.2 7.0 0.0 0.0 2548.9 2.283 2163.5 0.238 0.0 0.0 230 16.5 6.8 0.0 0.0 2528.4 2.265 2128.9 0.250 0.0 0.0 240 16.7 6.6 0.0 0.0 2508.0 2.246 2094.7 0.262 0.0 0.0 250 16.8 6.4 0.0 0.0 2487.8 2.228 2061.0 0.274 0.0 0.0 260 17.0 6.2 0.0 0.0 2467.6 2.210 2027.7 0.286 0.0 0.0 270 17.0 6.0 0.0 0.0 2447.5 2.192 1994.8 0.298 0.0 0.0 280 17.0 5.8 0.0 0.0 2427.5 2.174 1962.3 0.310 0.0 0.0 290 16.9 5.6 0.0 0.0 2407.6 2.156 1930.3 0.323 0.0 0.0 300 16.8 5.3 0.0 0.0 2387.8 2.139 1898.6 0.335 0.0 0.0 310 16.6 5.1 0.0 0.0 2368.0 2.121 1867.4 0.348 0.0 0.0 320 16.4 4.9 0.0 0.0 2348.4 2.103 1836.5 0.360 0.0 0.0 330 16.1 4.6 0.0 0.0 2328.9 2.086 1806.1 0.373 0.0 0.0 340 15.7 4.4 0.0 0.0 2309.4 2.068 1776.1 0.386 0.0 0.0 350 15.2 4.2 0.0 0.0 2290.0 2.051 1746.4 0.399 0.0 0.0 360 14.7 3.9 0.0 0.0 2270.8 2.034 1717.1 0.412 0.0 0.0 370 14.2 3.7 0.0 0.0 2251.6 2.017 1688.2 0.426 0.0 0.0 380 13.5 3.4 0.0 0.0 2232.5 2.000 1659.7 0.439 0.0 0.0 390 12.8 3.1 0.0 0.0 2213.5 1.983 1631.6 0.453 0.0 0.0 400 12.0 2.9 0.0 0.0 2194.5 1.966 1603.8 0.466 0.0 0.0 410 11.2 2.6 0.0 0.0 2175.7 1.949 1576.4 0.480 0.0 0.0 420 10.2 2.3 0.0 0.0 2157.0 1.932 1549.3 0.494 0.0 0.0 430 9.2 2.1 0.0 0.0 2138.3 1.915 1522.7 0.508 0.0 0.0 440 8.2 1.8 0.0 0.0 2119.8 1.899 1496.3 0.522 0.0 0.0 450 7.0 1.5 0.0 0.0 2101.3 1.882 1470.4 0.536 0.0 0.0 460 5.8 1.2 0.0 0.0 2082.9 1.866 1444.8 0.550 0.0 0.0 470 4.4 0.9 0.0 0.0 2064.6 1.849 1419.5 0.565 0.0 0.0 480 3.0 0.6 0.0 0.0 2046.4 1.833 1394.6 0.579 0.0 0.0 490 1.6 0.3 0.0 0.0 2028.3 1.817 1370.1 0.594 0.0 0.0 500 -0.0 -0.0 0.0 0.0 2010.3 1.801 1345.9 0.609 0.0 0.0 23/10/09 05:34, JBM/jbmtraj_simp-5.0.cgi
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Ghost
8 Point Buck
"Friendship must never be buried under the weight of misunderstanding."
Posts: 465
Likes: 0
Joined: May 14, 2024 7:14:03 GMT -5
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Post by Ghost on Oct 23, 2009 7:40:39 GMT -5
Like I said above my understanding of the G7 was ment to be used for ranges greater than 500 yrds.
Looking at the two models the difference out to 500 yards doesn't seem to be much to fuss about. But, if I am right lets look at the drop past 500 yards with both models. Remember I am taaking a shot in the dark on this.
This is the G7 from 600 yrds to 1000 yrds.
600 -19.1 -3.0 0.0 0.0 1954.1 1.750 1271.6 0.741 0.0 0.0 610 -21.5 -3.4 0.0 0.0 1938.4 1.736 1251.3 0.756 0.0 0.0 620 -23.9 -3.7 0.0 0.0 1922.8 1.722 1231.2 0.772 0.0 0.0 630 -26.5 -4.0 0.0 0.0 1907.2 1.708 1211.3 0.788 0.0 0.0 640 -29.2 -4.4 0.0 0.0 1891.7 1.694 1191.7 0.803 0.0 0.0 650 -31.9 -4.7 0.0 0.0 1876.3 1.681 1172.4 0.819 0.0 0.0 660 -34.8 -5.0 0.0 0.0 1860.9 1.667 1153.2 0.835 0.0 0.0 670 -37.8 -5.4 0.0 0.0 1845.6 1.653 1134.3 0.852 0.0 0.0 680 -40.8 -5.7 0.0 0.0 1830.4 1.639 1115.7 0.868 0.0 0.0 690 -44.0 -6.1 0.0 0.0 1815.2 1.626 1097.2 0.884 0.0 0.0 700 -47.3 -6.4 0.0 0.0 1800.0 1.612 1079.0 0.901 0.0 0.0 710 -50.6 -6.8 0.0 0.0 1785.0 1.599 1061.0 0.918 0.0 0.0 720 -54.1 -7.2 0.0 0.0 1769.9 1.585 1043.2 0.935 0.0 0.0 730 -57.7 -7.6 0.0 0.0 1755.0 1.572 1025.6 0.952 0.0 0.0 740 -61.5 -7.9 0.0 0.0 1740.0 1.559 1008.3 0.969 0.0 0.0 750 -65.3 -8.3 0.0 0.0 1725.2 1.545 991.1 0.986 0.0 0.0 760 -69.2 -8.7 0.0 0.0 1710.4 1.532 974.2 1.004 0.0 0.0 770 -73.3 -9.1 0.0 0.0 1695.6 1.519 957.5 1.021 0.0 0.0 780 -77.5 -9.5 0.0 0.0 1680.9 1.506 940.9 1.039 0.0 0.0 790 -81.8 -9.9 0.0 0.0 1666.3 1.492 924.6 1.057 0.0 0.0 800 -86.2 -10.3 0.0 0.0 1651.7 1.479 908.5 1.075 0.0 0.0 810 -90.8 -10.7 0.0 0.0 1637.2 1.466 892.6 1.093 0.0 0.0 820 -95.5 -11.1 0.0 0.0 1622.7 1.453 876.8 1.112 0.0 0.0 830 -100.3 -11.5 0.0 0.0 1608.2 1.440 861.3 1.130 0.0 0.0 840 -105.3 -12.0 0.0 0.0 1593.9 1.428 846.0 1.149 0.0 0.0 850 -110.3 -12.4 0.0 0.0 1579.5 1.415 830.8 1.168 0.0 0.0 860 -115.6 -12.8 0.0 0.0 1565.3 1.402 815.9 1.187 0.0 0.0 870 -121.0 -13.3 0.0 0.0 1551.1 1.389 801.2 1.206 0.0 0.0 880 -126.5 -13.7 0.0 0.0 1536.9 1.377 786.6 1.226 0.0 0.0 890 -132.1 -14.2 0.0 0.0 1522.8 1.364 772.2 1.245 0.0 0.0 900 -138.0 -14.6 0.0 0.0 1508.8 1.351 758.1 1.265 0.0 0.0 910 -143.9 -15.1 0.0 0.0 1494.8 1.339 744.1 1.285 0.0 0.0 920 -150.0 -15.6 0.0 0.0 1480.9 1.326 730.3 1.305 0.0 0.0 930 -156.3 -16.1 0.0 0.0 1467.0 1.314 716.7 1.325 0.0 0.0 940 -162.8 -16.5 0.0 0.0 1453.2 1.302 703.2 1.346 0.0 0.0 950 -169.4 -17.0 0.0 0.0 1439.4 1.289 690.0 1.367 0.0 0.0 960 -176.2 -17.5 0.0 0.0 1425.8 1.277 676.9 1.388 0.0 0.0 970 -183.1 -18.0 0.0 0.0 1412.1 1.265 664.1 1.409 0.0 0.0 980 -190.2 -18.5 0.0 0.0 1398.6 1.253 651.4 1.430 0.0 0.0 990 -197.5 -19.1 0.0 0.0 1385.1 1.241 638.9 1.452 0.0 0.0 1000 -205.0 -19.6 0.0 0.0 1371.7 1.229 626.6 1.474 0.0 0.0
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Ghost
8 Point Buck
"Friendship must never be buried under the weight of misunderstanding."
Posts: 465
Likes: 0
Joined: May 14, 2024 7:14:03 GMT -5
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Post by Ghost on Oct 23, 2009 7:42:43 GMT -5
Now for the G1 from 600 yards to a grand.
600 -20.6 -3.3 0.0 0.0 1835.8 1.644 1122.3 0.765 0.0 0.0 610 -23.2 -3.6 0.0 0.0 1818.9 1.629 1101.7 0.782 0.0 0.0 620 -26.0 -4.0 0.0 0.0 1802.1 1.614 1081.5 0.798 0.0 0.0 630 -28.8 -4.4 0.0 0.0 1785.4 1.599 1061.5 0.815 0.0 0.0 640 -31.7 -4.7 0.0 0.0 1768.8 1.584 1041.9 0.832 0.0 0.0 650 -34.7 -5.1 0.0 0.0 1752.4 1.570 1022.6 0.849 0.0 0.0 660 -37.9 -5.5 0.0 0.0 1736.1 1.555 1003.7 0.866 0.0 0.0 670 -41.1 -5.9 0.0 0.0 1719.8 1.540 985.0 0.883 0.0 0.0 680 -44.5 -6.3 0.0 0.0 1703.7 1.526 966.6 0.901 0.0 0.0 690 -48.0 -6.6 0.0 0.0 1687.7 1.512 948.6 0.919 0.0 0.0 700 -51.6 -7.0 0.0 0.0 1671.9 1.497 930.8 0.936 0.0 0.0 710 -55.4 -7.4 0.0 0.0 1656.1 1.483 913.4 0.954 0.0 0.0 720 -59.3 -7.9 0.0 0.0 1640.5 1.469 896.2 0.973 0.0 0.0 730 -63.3 -8.3 0.0 0.0 1625.0 1.456 879.4 0.991 0.0 0.0 740 -67.4 -8.7 0.0 0.0 1609.7 1.442 862.8 1.010 0.0 0.0 750 -71.7 -9.1 0.0 0.0 1594.4 1.428 846.6 1.028 0.0 0.0 760 -76.1 -9.6 0.0 0.0 1579.3 1.415 830.6 1.047 0.0 0.0 770 -80.6 -10.0 0.0 0.0 1564.4 1.401 815.0 1.066 0.0 0.0 780 -85.3 -10.4 0.0 0.0 1549.6 1.388 799.6 1.086 0.0 0.0 790 -90.1 -10.9 0.0 0.0 1534.9 1.375 784.5 1.105 0.0 0.0 800 -95.1 -11.4 0.0 0.0 1520.3 1.362 769.7 1.125 0.0 0.0 810 -100.2 -11.8 0.0 0.0 1505.9 1.349 755.2 1.144 0.0 0.0 820 -105.5 -12.3 0.0 0.0 1491.7 1.336 741.0 1.165 0.0 0.0 830 -111.0 -12.8 0.0 0.0 1477.6 1.323 727.0 1.185 0.0 0.0 840 -116.5 -13.2 0.0 0.0 1463.6 1.311 713.4 1.205 0.0 0.0 850 -122.3 -13.7 0.0 0.0 1449.8 1.299 700.0 1.226 0.0 0.0 860 -128.2 -14.2 0.0 0.0 1436.2 1.286 686.9 1.247 0.0 0.0 870 -134.3 -14.7 0.0 0.0 1422.7 1.274 674.0 1.267 0.0 0.0 880 -140.6 -15.3 0.0 0.0 1409.4 1.262 661.5 1.289 0.0 0.0 890 -147.0 -15.8 0.0 0.0 1396.2 1.251 649.2 1.310 0.0 0.0 900 -153.6 -16.3 0.0 0.0 1383.2 1.239 637.2 1.332 0.0 0.0 910 -160.4 -16.8 0.0 0.0 1370.4 1.227 625.4 1.353 0.0 0.0 920 -167.4 -17.4 0.0 0.0 1357.8 1.216 613.9 1.375 0.0 0.0 930 -174.6 -17.9 0.0 0.0 1345.3 1.205 602.7 1.398 0.0 0.0 940 -182.0 -18.5 0.0 0.0 1333.0 1.194 591.7 1.420 0.0 0.0 950 -189.5 -19.1 0.0 0.0 1320.9 1.183 581.0 1.443 0.0 0.0 960 -197.3 -19.6 0.0 0.0 1309.0 1.172 570.6 1.465 0.0 0.0 970 -205.3 -20.2 0.0 0.0 1297.3 1.162 560.4 1.489 0.0 0.0 980 -213.4 -20.8 0.0 0.0 1285.8 1.152 550.5 1.512 0.0 0.0 990 -221.8 -21.4 0.0 0.0 1274.4 1.141 540.9 1.535 0.0 0.0 1000 -230.4 -22.0 0.0 0.0 1263.3 1.131 531.4 1.559 0.0 0.0
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Ghost
8 Point Buck
"Friendship must never be buried under the weight of misunderstanding."
Posts: 465
Likes: 0
Joined: May 14, 2024 7:14:03 GMT -5
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Post by Ghost on Oct 23, 2009 7:43:57 GMT -5
almost 2 1/2 feet of difference @ a grand between the two. If I did this right, this is amazing.
Going over the numbers they look okay. I ran the G7 again but this time setting the program to figure in the MPBR and the MPBR Zero and this is what it looks like.
Trajectory (Simplified) Input Data Ballistic Coefficient: 0.246 G7 Caliber: 0.308 in Bullet Weight: 150.0 gr Muzzle Velocity: 3025.0 ft/s Sight Height: 2.00 in Line Of Sight Angle: 0.0 deg Cant Angle: 0.0 deg Wind Speed: 0.0 mph Target Speed: 0.0 mph Temperature: 59.0 °F Pressure: 29.92 in Hg Humidity: 0.0 % Altitude: 0.0 ft Std. Atmosphere at Altitude: No Pressure is Corrected: Yes Zero at Max. Point Blank Range: Yes Target Relative Drops: Yes Round Output to Whole Numbers: No Output Data Elevation: 7.246 MOA Windage: 0.000 MOA Atmospheric Density: 0.07647 lb/ft³ Speed of Sound: 1116.5 ft/s Maximum PBR: 371 yd Maximum PBR Zero: 316 yd Range of Maximum Height: 177 yd Energy at Maximum PBR: 1811.1 ft•lbs Sectional Density: 0.226 lb/in² Calculated Table Range Drop Drop Windage Windage Velocity Mach Energy Time Lead Lead (yd) (in) (MOA) (in) (MOA) (ft/s) (none) (ft•lbs) (s) (in) (MOA) 10 -1.3 -12.0 0.0 0.0 3005.2 2.692 3007.4 0.010 0.0 0.0 20 -0.6 -2.7 0.0 0.0 2985.4 2.674 2967.9 0.020 0.0 0.0 30 0.1 0.3 0.0 0.0 2965.6 2.656 2928.8 0.030 0.0 0.0 40 0.7 1.7 0.0 0.0 2946.0 2.639 2890.1 0.040 0.0 0.0 50 1.3 2.5 0.0 0.0 2926.4 2.621 2851.8 0.050 0.0 0.0 60 1.9 2.9 0.0 0.0 2906.8 2.604 2813.8 0.061 0.0 0.0 70 2.4 3.2 0.0 0.0 2887.3 2.586 2776.2 0.071 0.0 0.0 80 2.8 3.4 0.0 0.0 2867.9 2.569 2738.9 0.081 0.0 0.0 90 3.2 3.4 0.0 0.0 2848.5 2.551 2702.1 0.092 0.0 0.0 100 3.6 3.4 0.0 0.0 2829.2 2.534 2665.6 0.103 0.0 0.0 110 3.9 3.4 0.0 0.0 2810.0 2.517 2629.4 0.113 0.0 0.0 120 4.2 3.4 0.0 0.0 2790.8 2.500 2593.7 0.124 0.0 0.0 130 4.5 3.3 0.0 0.0 2771.7 2.483 2558.3 0.135 0.0 0.0 140 4.7 3.2 0.0 0.0 2752.6 2.465 2523.2 0.146 0.0 0.0 150 4.8 3.1 0.0 0.0 2733.6 2.448 2488.5 0.156 0.0 0.0 160 4.9 2.9 0.0 0.0 2714.7 2.432 2454.2 0.167 0.0 0.0 170 5.0 2.8 0.0 0.0 2695.9 2.415 2420.3 0.179 0.0 0.0 180 5.0 2.6 0.0 0.0 2677.1 2.398 2386.6 0.190 0.0 0.0 190 4.9 2.5 0.0 0.0 2658.4 2.381 2353.4 0.201 0.0 0.0 200 4.9 2.3 0.0 0.0 2639.8 2.364 2320.5 0.212 0.0 0.0 210 4.7 2.1 0.0 0.0 2621.2 2.348 2288.0 0.224 0.0 0.0 220 4.5 2.0 0.0 0.0 2602.7 2.331 2255.8 0.235 0.0 0.0 230 4.3 1.8 0.0 0.0 2584.3 2.315 2224.0 0.247 0.0 0.0 240 4.0 1.6 0.0 0.0 2565.9 2.298 2192.5 0.258 0.0 0.0 250 3.7 1.4 0.0 0.0 2547.6 2.282 2161.3 0.270 0.0 0.0 260 3.3 1.2 0.0 0.0 2529.4 2.266 2130.5 0.282 0.0 0.0 270 2.8 1.0 0.0 0.0 2511.3 2.249 2100.1 0.294 0.0 0.0 280 2.3 0.8 0.0 0.0 2493.2 2.233 2070.0 0.306 0.0 0.0 290 1.7 0.6 0.0 0.0 2475.2 2.217 2040.2 0.318 0.0 0.0 300 1.1 0.4 0.0 0.0 2457.2 2.201 2010.7 0.330 0.0 0.0 310 0.4 0.1 0.0 0.0 2439.4 2.185 1981.6 0.342 0.0 0.0 320 -0.3 -0.1 0.0 0.0 2421.6 2.169 1952.8 0.355 0.0 0.0 330 -1.1 -0.3 0.0 0.0 2403.9 2.153 1924.4 0.367 0.0 0.0 340 -2.0 -0.5 0.0 0.0 2386.3 2.137 1896.3 0.380 0.0 0.0 350 -2.9 -0.8 0.0 0.0 2368.7 2.122 1868.4 0.392 0.0 0.0 360 -3.8 -1.0 0.0 0.0 2351.2 2.106 1841.0 0.405 0.0 0.0 370 -4.9 -1.3 0.0 0.0 2333.8 2.090 1813.8 0.418 0.0 0.0 380 -6.0 -1.5 0.0 0.0 2316.5 2.075 1786.9 0.431 0.0 0.0 390 -7.2 -1.8 0.0 0.0 2299.2 2.059 1760.4 0.444 0.0 0.0 400 -8.4 -2.0 0.0 0.0 2282.0 2.044 1734.2 0.457 0.0 0.0 410 -9.7 -2.3 0.0 0.0 2264.9 2.029 1708.3 0.470 0.0 0.0 420 -11.1 -2.5 0.0 0.0 2247.9 2.013 1682.7 0.483 0.0 0.0 430 -12.5 -2.8 0.0 0.0 2230.9 1.998 1657.4 0.497 0.0 0.0 440 -14.0 -3.0 0.0 0.0 2214.1 1.983 1632.4 0.510 0.0 0.0 450 -15.6 -3.3 0.0 0.0 2197.3 1.968 1607.8 0.524 0.0 0.0 460 -17.2 -3.6 0.0 0.0 2180.6 1.953 1583.4 0.538 0.0 0.0 470 -19.0 -3.9 0.0 0.0 2163.9 1.938 1559.3 0.551 0.0 0.0 480 -20.8 -4.1 0.0 0.0 2147.3 1.923 1535.5 0.565 0.0 0.0 490 -22.6 -4.4 0.0 0.0 2130.9 1.909 1512.0 0.579 0.0 0.0 500 -24.6 -4.7 0.0 0.0 2114.4 1.894 1488.8 0.593 0.0 0.0
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Post by 4Pointer on Oct 23, 2009 16:43:23 GMT -5
I'M LOST... WHAT YOU SAID SOUNDS GOOD TOO ME ;D
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Post by Kt29 on Oct 23, 2009 17:42:33 GMT -5
Hey soggy. Not sure how much help I can be here. But enclosed is the program that I use. They have an Advanced program that you can get into also. I can say though, that of all my big game bullets that I load. The Accubonds are by far the most accurate. Hope ya get it figured out. I would be interested to learn more also. www.biggameinfo.com/index.aspx?&page=%2fbalcalc.ascx
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Ghost
8 Point Buck
"Friendship must never be buried under the weight of misunderstanding."
Posts: 465
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Joined: May 14, 2024 7:14:03 GMT -5
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Post by Ghost on Oct 23, 2009 20:40:04 GMT -5
In my endevour to understand the G7 model I have ran across mathmatic problems that belong on an MIT chalk board, pages linked to aerospace engineering, pages linked to NASA, ect . My first understanding or education when getting into this subject is it's rather difficult to calculate on your own, at least for the average person. I believe I might be close to solving the matter of coming up with the BC for the G7 model, but further research is needed to prove or disprove the theory above. What I do know is, that applying the correct drag model can make a big difference in how the ballistic tables are set up. I also know that less than 500 yards the difference between any two drag models can be minimal +/- a few inches. To the average shooter that is not going to take his setup past 500 yards, the minor difference probably means nothing. For the shooter that wants to best understand the ballistics (in theory/paper) past 500 yards can mean the difference between a hit and a miss. This given, the margin for error goes up greatly past 500 yards if the incorrect drag model is applied. Now, I am not saying that the incorrect drag model for ranges below 500 yards can be taken lightly, but the margin for error is a little more forgiving.
One needs to also understand that any ballistic table appiled under any drag model is an educated guess, or at best a finer estimation. Like any theory, it may look good on paper, but realality is unforgiving.
I think my theory (above tables) is close to true, as far as this bullet type is concerned. Further research is needed to prove or disprove my theory. I need to find and run other programs that have the ability to convert the G1 to the G7. We all know that the programs used to produce ballistic tables can vary form one program to the next, depending on the designer of the software. Right now the only way I know how to get around this is to compare programs against each other and find credible authors.
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Ghost
8 Point Buck
"Friendship must never be buried under the weight of misunderstanding."
Posts: 465
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Joined: May 14, 2024 7:14:03 GMT -5
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Post by Ghost on Oct 23, 2009 21:02:49 GMT -5
I find this interesting. By reading the above information we know that the G1 is best suited for ranges under 500 yards. The BC that is given by the manufacturer is also applied to the G1 drag model, which in turn makes the BC given look better than it really is. Tke the bullet in the above senerio. It has a BC of 0.435. When applying this to any given ballistic chart it is rather accurate up to 500 yards +/- inch. Now, look at the average box of factory ammo and look for the provided ballistics chart that is taped somewhere on the box. You will never see them take their ballistics past 500 yards. Why? This in turn proves that the correct drag model needs to be applied. If manufacturers used the correct drag model for the bullet sold in a specific box, I bet the BC would be cut by a third if not in half. With high BC's being a determining factor on sales at the retail counter the G1 becomes a selling point, however incorrect it may be.
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Head Hunter
4 Pointer
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Post by Head Hunter on Oct 24, 2009 13:58:40 GMT -5
Take this from a Ex-Army shooter. I have used all the different Programs out there, yes alot of them are great and help out alot. But I feel alot of people are getting to rely on them instead of the true test. There is nothing better then true data. I create a log book for every rifle I own. There is no true date then the one you get from your rifle with you pulling the triger.
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Ghost
8 Point Buck
"Friendship must never be buried under the weight of misunderstanding."
Posts: 465
Likes: 0
Joined: May 14, 2024 7:14:03 GMT -5
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Post by Ghost on Oct 24, 2009 15:04:28 GMT -5
I agree Kroger, there is no replacement for real time data. But, what I am trying to get to is how the G7 drag model is applied and used. Mainly the BC as it relates to the G7. Aside from what the gun is actually capable of, the question is more directly geared towards a lack of knowledge about this side of the puzzle. The logs or tables that I create before hand are just that, preliminary. The give me a ball park figure at where to start. I find myself in agreement that if a shooter relies solely on a computer generated program they will find themselves scratching their head at the end of the day.
Glad to have you here Kroger. I am also going to make a post later on about the use of a 20 MOA picatiny base. Please forgive me for the severe lack of knowledge on this type of base. But, by the time I post I will have a decent understanding of its application and better apt to carry on a conversation about the subject. As for know I know diddly squat. So Kroger and KT keep a look out for the post it is coming.
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Post by Kt29 on Oct 25, 2009 12:28:44 GMT -5
Lookin forward to it.
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