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Rifles, Reloading, Optics, Equipment
Rifles, Bullets, Barrels & Ballistics
Quest for g7 ballistics programs (can we please make a list)
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<blockquote data-quote="BryanLitz" data-source="post: 305593" data-attributes="member: 7848"><p>Great discussion!</p><p></p><p>First I'd like to thank those who've set me straight on the G7 capable software; turns out LoadBase doesn't accept G7 BC's as I thought it did. It's been removed from the list.</p><p></p><p>I sure wish I was a smarter programmer and had the time, there's a real strong market for G7 capable PDA's. Right now, if you don't have an iPhone, it seems there aren't any options.</p><p></p><p>Lou,</p><p></p><p>You bring up a good point about computational resources, and the possibility of using unique drag curves for each bullet. Computers certainly aren't preventing us from doing that, but I think there are still other very practical and useful reasons to continue the use of BC's.</p><p></p><p>First, BC contains more than just drag information. It includes sectional density, and is an important 'comparison' number to use.</p><p></p><p>Second, there isn't enough experimental data to start using it exclusively. If you use </p><p>McDrag or some other computer prediction program, you're looking at +/- 10% error and it's no better than an estimated G1 BC.</p><p></p><p>My experimental data is collected using acoustic sensors, which means they only work (well) during the supersonic portion of the bullets flight. Using a BC referenced to a standard projectile, you can extrapolate the measured, high speed data down to transonic and subsonic speeds. You can also extrapolate to higher speeds than those tested because the standard curve is known. If you rely <em>only</em> on measured data, you can only predict trajectories over speed ranges that you've actually measured and that is a practical limitation.</p><p></p><p>When radar data exists, it's usually quite good and can be used to calculate very accurate trajectories. However, it's unlikely that such data will exist in bulk any time soon for anyone other than Lapua. </p><p></p><p>If you look at trajectories predicted with Lapua's direct drag data compared to a G7 BC that's based on the drag data, there is very little difference between the two trajectories at all ranges. There's certainly much less difference than a G1 vs G7 based trajectory.</p><p></p><p>I like to think of the move to G7 BCs as an important and practical improvement in the potential accuracy of ballistic calculations. Is it <em>the most</em> precise way? No. But it's the point of diminishing returns between complexity and accuracy. In other words, going to G7 BC's removes 90% to 95% of the velocity dependence problems associated with G1's, and most hunters/shooters can adopt the G7 BC's with little pain and confusion (provided the mobile software becomes available). Getting that last 5% to 10% would require using many other standards (G2, G5, etc...) or raw drag data unique to each bullet. There's no reason for some curious individuals not to explore these more complex options for their own use, but I don't feel they're the right solution for general use. Of course, that is a matter of my opinion, and is arguable.</p><p></p><p>I need to get on the ball and learn how to program PDA's already!</p><p></p><p>-Bryan</p></blockquote><p></p>
[QUOTE="BryanLitz, post: 305593, member: 7848"] Great discussion! First I'd like to thank those who've set me straight on the G7 capable software; turns out LoadBase doesn't accept G7 BC's as I thought it did. It's been removed from the list. I sure wish I was a smarter programmer and had the time, there's a real strong market for G7 capable PDA's. Right now, if you don't have an iPhone, it seems there aren't any options. Lou, You bring up a good point about computational resources, and the possibility of using unique drag curves for each bullet. Computers certainly aren't preventing us from doing that, but I think there are still other very practical and useful reasons to continue the use of BC's. First, BC contains more than just drag information. It includes sectional density, and is an important 'comparison' number to use. Second, there isn't enough experimental data to start using it exclusively. If you use McDrag or some other computer prediction program, you're looking at +/- 10% error and it's no better than an estimated G1 BC. My experimental data is collected using acoustic sensors, which means they only work (well) during the supersonic portion of the bullets flight. Using a BC referenced to a standard projectile, you can extrapolate the measured, high speed data down to transonic and subsonic speeds. You can also extrapolate to higher speeds than those tested because the standard curve is known. If you rely [i]only[/i] on measured data, you can only predict trajectories over speed ranges that you've actually measured and that is a practical limitation. When radar data exists, it's usually quite good and can be used to calculate very accurate trajectories. However, it's unlikely that such data will exist in bulk any time soon for anyone other than Lapua. If you look at trajectories predicted with Lapua's direct drag data compared to a G7 BC that's based on the drag data, there is very little difference between the two trajectories at all ranges. There's certainly much less difference than a G1 vs G7 based trajectory. I like to think of the move to G7 BCs as an important and practical improvement in the potential accuracy of ballistic calculations. Is it [i]the most[/i] precise way? No. But it's the point of diminishing returns between complexity and accuracy. In other words, going to G7 BC's removes 90% to 95% of the velocity dependence problems associated with G1's, and most hunters/shooters can adopt the G7 BC's with little pain and confusion (provided the mobile software becomes available). Getting that last 5% to 10% would require using many other standards (G2, G5, etc...) or raw drag data unique to each bullet. There's no reason for some curious individuals not to explore these more complex options for their own use, but I don't feel they're the right solution for general use. Of course, that is a matter of my opinion, and is arguable. I need to get on the ball and learn how to program PDA's already! -Bryan [/QUOTE]
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Quest for g7 ballistics programs (can we please make a list)
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