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Rifles, Reloading, Optics, Equipment
Rifles, Bullets, Barrels & Ballistics
MERC - Maximum Effective Range Calculator
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<blockquote data-quote="speedengineer" data-source="post: 1969866" data-attributes="member: 112986"><p>...continued...</p><p></p><p>Ok, set Range uncertainty back to zero. Now let's set wind speed uncertainty to 20%. </p><p>Because the wind speed for each shot is different than the nominal wind speed that you hold for, your hits will spread out horizontally. </p><p>[ATTACH=full]211535[/ATTACH]</p><p>[ATTACH=full]211536[/ATTACH]</p><p></p><p></p><p>Let's set wind speed uncertainty back to zero, and set wind angle uncertainty to 25 degrees. </p><p>Because we are shooting in a 10mph 'full value' crosswind, any error/deviation in wind direction from that 90 degrees results in LESS crosswind speed than the shooter held for. Example, if wind direction uncertainty for a particular shot was 20 degrees less than actual, then the wind angle used for the shot would be 70 degrees, which will result in less crosswind speed than 10mph. Actually for this case, it would be 9.4 mph. Because of this effect, and wind angle uncertainty with a crosswind will results in shots impacting the target only towards the upwind side!!! Very interesting to note this, as it means that your groupings can become non-centered around your point of aim when shooting in a crosswind situation with variable wind direction! You may even attain a better hit percentage by aiming slightly downwind of your target center. You can experiment with this by entering a 'horizontal scope error' value into MERC.</p><p>[ATTACH=full]211537[/ATTACH]</p><p>[ATTACH=full]211538[/ATTACH]</p><p></p><p>Lastly, let's combine all of the above mentioned uncertainties together. This shows the total combined effect of everything acting together to affect your rifles accuracy, hit locations, and resulting hit percentage!</p><p>1 MOA</p><p>10fps MVSD</p><p>10yd Range Uncertainty</p><p>20% Wind Speed Uncertainty</p><p>25 degree Wind Angle Uncertainty</p><p>[ATTACH=full]211539[/ATTACH]</p><p>[ATTACH=full]211540[/ATTACH]</p></blockquote><p></p>
[QUOTE="speedengineer, post: 1969866, member: 112986"] ...continued... Ok, set Range uncertainty back to zero. Now let's set wind speed uncertainty to 20%. Because the wind speed for each shot is different than the nominal wind speed that you hold for, your hits will spread out horizontally. [ATTACH type="full"]211535[/ATTACH] [ATTACH type="full"]211536[/ATTACH] Let's set wind speed uncertainty back to zero, and set wind angle uncertainty to 25 degrees. Because we are shooting in a 10mph 'full value' crosswind, any error/deviation in wind direction from that 90 degrees results in LESS crosswind speed than the shooter held for. Example, if wind direction uncertainty for a particular shot was 20 degrees less than actual, then the wind angle used for the shot would be 70 degrees, which will result in less crosswind speed than 10mph. Actually for this case, it would be 9.4 mph. Because of this effect, and wind angle uncertainty with a crosswind will results in shots impacting the target only towards the upwind side!!! Very interesting to note this, as it means that your groupings can become non-centered around your point of aim when shooting in a crosswind situation with variable wind direction! You may even attain a better hit percentage by aiming slightly downwind of your target center. You can experiment with this by entering a 'horizontal scope error' value into MERC. [ATTACH type="full"]211537[/ATTACH] [ATTACH type="full"]211538[/ATTACH] Lastly, let's combine all of the above mentioned uncertainties together. This shows the total combined effect of everything acting together to affect your rifles accuracy, hit locations, and resulting hit percentage! 1 MOA 10fps MVSD 10yd Range Uncertainty 20% Wind Speed Uncertainty 25 degree Wind Angle Uncertainty [ATTACH type="full"]211539[/ATTACH] [ATTACH type="full"]211540[/ATTACH] [/QUOTE]
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MERC - Maximum Effective Range Calculator
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