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Rifles, Reloading, Optics, Equipment
Rifles, Bullets, Barrels & Ballistics
BEWARE, Problems with Exbal and G7 BC's
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<blockquote data-quote="Gustavo" data-source="post: 450935" data-attributes="member: 6"><p>Hi there,</p><p> </p><p>Just to clarify some points exposed on this very nice thread.</p><p> </p><p>1) LB3 does not use the Pejsa method.</p><p> </p><p>2) It's a propietary algorithm, with many extensions to Dr. Pejsa's method.</p><p> </p><p>3) During the development phase, Dr. Pejsa was very kind to discuss the new algorithm math and that's why he is credited as having provided the original concept.</p><p> </p><p>4) The current algorithm employed in LB3 took over two years to develop, and the only part that has some resemblances is in how to model the Drag curve.</p><p> </p><p>5) Both methods (LB3 and Pejsa) are all abouth MACH when modeling the drag curve. I think this is one of the less understood aspects of how the algorithm actually works.</p><p> </p><p>Please check the following article that shows some differences in the predictions made by some methods.</p><p> </p><p><a href="http://www.longrangehunting.com/articles/ballistics-predictions-1.php" target="_blank"><span style="font-size: 15px">Ballistics and Predictions</span></a></p><p> </p><p>While the article does not discuss the inner aspects of the algorithms and the math behind them (clearly out of scope), the general idea is exposed when comparing their outcome. </p><p> </p><p><em><span style="font-size: 10px"><span style="color: black">The Point Mass (3DOF) method is used by the following free and commercially available ballistics programs: JBM (web), Berger, Litz, RSI, Ballistics FTE (iPhone), iSnipe (iPhone), BulletFlight (iPhone), Shooter (Android), FieldCraft (ex ABC by CheyTac), Balistika, Quick Target Unlimited, JBallistics, BigGameInfo (web) plus many others. The algorithm is well known and free computer code is available to download from the Internet. </span></span></em></p><p> </p><p><em><span style="font-size: 10px"><span style="color: black">The Pejsa method is used by the following free and commercially available ballistics programs: FFS (Field Firing Solutions), BallistiX, Dr. Pejsa's own plus some free spreadsheets like BfX. One of the typical issues that are encountered with most of the usual solutions is that they are limited to supersonic velocity values, something very critical to take into consideration when evaluating these programs. The algorithm can be studied in the books published by the author.</span></span></em></p><p> </p><p>Some graphs of actual Doppler radar data, compared to LoadBase 3.0 (Desktop and Mobile) predictions.</p><p> </p><p> </p><p><strong><span style="font-size: 15px">.338 Lapua Magnum (radar data provided by Lapua)</span></strong></p><p> </p><p> </p><p><img src="http://i182.photobucket.com/albums/x181/GustavoFabianRuiz/LoadBase3_Doppler_338LM_DROP_DELTA_ALL.jpg" alt="" class="fr-fic fr-dii fr-draggable " style="" /></p><p> </p><p><img src="http://i182.photobucket.com/albums/x181/GustavoFabianRuiz/LoadBase3_Doppler_338LM_DROP_DELTA_DETAIL.jpg" alt="" class="fr-fic fr-dii fr-draggable " style="" /></p><p> </p><p></p><p><strong><span style="font-size: 15px">.50 BMG (radar data provided by a NATO facility, taken about a month ago)</span></strong></p><p></p><p> </p><p><img src="http://i182.photobucket.com/albums/x181/GustavoFabianRuiz/LoadBase3_Doppler_50BMG_DROP_DELTA.jpg" alt="" class="fr-fic fr-dii fr-draggable " style="" /></p><p> </p><p><img src="http://i182.photobucket.com/albums/x181/GustavoFabianRuiz/LoadBase3_Doppler_50BMG_VELOCITY_DELTA.jpg" alt="" class="fr-fic fr-dii fr-draggable " style="" /></p></blockquote><p></p>
[QUOTE="Gustavo, post: 450935, member: 6"] Hi there, Just to clarify some points exposed on this very nice thread. 1) LB3 does not use the Pejsa method. 2) It's a propietary algorithm, with many extensions to Dr. Pejsa's method. 3) During the development phase, Dr. Pejsa was very kind to discuss the new algorithm math and that's why he is credited as having provided the original concept. 4) The current algorithm employed in LB3 took over two years to develop, and the only part that has some resemblances is in how to model the Drag curve. 5) Both methods (LB3 and Pejsa) are all abouth MACH when modeling the drag curve. I think this is one of the less understood aspects of how the algorithm actually works. Please check the following article that shows some differences in the predictions made by some methods. [URL="http://www.longrangehunting.com/articles/ballistics-predictions-1.php"][SIZE=4]Ballistics and Predictions[/SIZE][/URL] While the article does not discuss the inner aspects of the algorithms and the math behind them (clearly out of scope), the general idea is exposed when comparing their outcome. [I][SIZE=2][COLOR=black]The Point Mass (3DOF) method is used by the following free and commercially available ballistics programs: JBM (web), Berger, Litz, RSI, Ballistics FTE (iPhone), iSnipe (iPhone), BulletFlight (iPhone), Shooter (Android), FieldCraft (ex ABC by CheyTac), Balistika, Quick Target Unlimited, JBallistics, BigGameInfo (web) plus many others. The algorithm is well known and free computer code is available to download from the Internet. [/COLOR][/SIZE][/I] [I][SIZE=2][COLOR=black]The Pejsa method is used by the following free and commercially available ballistics programs: FFS (Field Firing Solutions), BallistiX, Dr. Pejsa’s own plus some free spreadsheets like BfX. One of the typical issues that are encountered with most of the usual solutions is that they are limited to supersonic velocity values, something very critical to take into consideration when evaluating these programs. The algorithm can be studied in the books published by the author.[/COLOR][/SIZE][/I] Some graphs of actual Doppler radar data, compared to LoadBase 3.0 (Desktop and Mobile) predictions. [B][SIZE=4].338 Lapua Magnum (radar data provided by Lapua)[/SIZE][/B] [IMG]http://i182.photobucket.com/albums/x181/GustavoFabianRuiz/LoadBase3_Doppler_338LM_DROP_DELTA_ALL.jpg[/IMG] [IMG]http://i182.photobucket.com/albums/x181/GustavoFabianRuiz/LoadBase3_Doppler_338LM_DROP_DELTA_DETAIL.jpg[/IMG] [B][SIZE=4].50 BMG (radar data provided by a NATO facility, taken about a month ago)[/SIZE][/B] [IMG]http://i182.photobucket.com/albums/x181/GustavoFabianRuiz/LoadBase3_Doppler_50BMG_DROP_DELTA.jpg[/IMG] [IMG]http://i182.photobucket.com/albums/x181/GustavoFabianRuiz/LoadBase3_Doppler_50BMG_VELOCITY_DELTA.jpg[/IMG] [/QUOTE]
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