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Elevation and ballistics
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<blockquote data-quote="700" data-source="post: 7546" data-attributes="member: 674"><p>Brent</p><p></p><p>You are quite wright about the +0.28 MOA measurment. I rechecked and found I misread the altitude correction. It should have been +0.028MOA altitude correction at 100 yards. Then add the -0.006 MOA temperature adjustment and I get +0.022 MOA. Read + as point of impact moves higher. That is pretty close to what you have.</p><p></p><p>How embarrasing! </p><p></p><p></p><p>A few other differences between our calculations are:</p><p></p><p>1) You are using Army Metro where as I am using ICAO with a 78% Humidity adjustment added in.</p><p>2) I used the 3 ballistic coefficients of </p><p>.505 @ 2800 fps and above</p><p>.496 between 2800 and 1800 fps</p><p>.485 @ 1800 fps and below</p><p>quoted on Sierras web site.</p><p></p><p></p><p>.496 is applicable to this cartridge out to about 500 yards.</p><p></p><p>3) Although generated by software, the charts I was referancing are paper charts and so not as accurate as typing parameters into a dialog box and hittig the OK button.</p><p></p><p>The charts take a basezero at sealevel and show how in turn altitude , temperature, humidity about that base zero affects the tradjectory. When these variations are taken in concert the charts can only give a rough approximation. But they work pretty good.</p><p></p><p>Brent,thanks for taking the time to check the calculations and point out my error. </p><p></p><p></p><p>Rgds</p><p></p><p>700</p></blockquote><p></p>
[QUOTE="700, post: 7546, member: 674"] Brent You are quite wright about the +0.28 MOA measurment. I rechecked and found I misread the altitude correction. It should have been +0.028MOA altitude correction at 100 yards. Then add the -0.006 MOA temperature adjustment and I get +0.022 MOA. Read + as point of impact moves higher. That is pretty close to what you have. How embarrasing! A few other differences between our calculations are: 1) You are using Army Metro where as I am using ICAO with a 78% Humidity adjustment added in. 2) I used the 3 ballistic coefficients of .505 @ 2800 fps and above .496 between 2800 and 1800 fps .485 @ 1800 fps and below quoted on Sierras web site. .496 is applicable to this cartridge out to about 500 yards. 3) Although generated by software, the charts I was referancing are paper charts and so not as accurate as typing parameters into a dialog box and hittig the OK button. The charts take a basezero at sealevel and show how in turn altitude , temperature, humidity about that base zero affects the tradjectory. When these variations are taken in concert the charts can only give a rough approximation. But they work pretty good. Brent,thanks for taking the time to check the calculations and point out my error. Rgds 700 [/QUOTE]
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