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  1. P

    Labrabaco: a G7 BC calculator from Labradar tracks

    For the record: I entirely agree with the opinion of Cal from PRB, quoted above, and with the unnamed "industry pro" that he is referring to. Because of obvious power limits, it is totally illusory to expect Labradar to produce meaningful data for a full bullet-specific Cd/Mach curve, or, as...
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    Another Picture Thread - All Other Semi-Autos

    Well, for correct terminology, here are a few gas guns then (mostly semi-autos).
  3. P

    Another Picture Thread - All Other Semi-Autos

    Strictly speaking, you're right -- it's recoil, not gas impingement.
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    Another Picture Thread - All Other Semi-Autos

    My favourite long-range .308 gas gun. A bit off-topic though, as it's not a semi-auto.
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    a geek’s delight: reverse engineer a distance-velocity table to Cd/Mach curve

    Time-of-flight based measurements? (Don't know, just guessing)
  6. P

    a geek’s delight: reverse engineer a distance-velocity table to Cd/Mach curve

    Yep, they (the Soviets) did so for bullet development, but the military trials were even more elegant. From what I've read, they were using time of flight as the base measure, which is much simpler to put in place at long range than velocity measurement -- just need to detect the shot, the...
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    Labrabaco: a G7 BC calculator from Labradar tracks

    Note to self: "Never play chess with pigeons - they knock over the pieces, shit all over the chessboard, and strut around convinced they've won."
  8. P

    Labrabaco: a G7 BC calculator from Labradar tracks

    I cannot help but wonder if I am the last person on the Internets who did not tell you yet that you are useless and boring. That would explain your frustration. Why don't you imagine yourself an opponent, and go argue imaginary arguments with voices in your head? -- you seem to be very good at...
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    Labrabaco: a G7 BC calculator from Labradar tracks

    The question of inflated BCs / significantly higher G7 BCs in the beginning of the trajectory is a tricky one. While it's certainly true for G1, just by the shape of the reference Cd curve vs. real spitzer boat tail drag profiles, with G7 I would almost expect the opposite (because of higher...
  10. P

    Labrabaco: a G7 BC calculator from Labradar tracks

    You are arguing with someone imaginary / voices in your head. SNR = 0, try again.
  11. P

    Labrabaco: a G7 BC calculator from Labradar tracks

    No. You have provided a fine example of flaming butthurt, which is not the same as real-world data and hard facts. In the starting post and in a couple of contributions to this thread there is a number of real-world examples of successful usage of Labradar + Labrabaco to obtain G7 BCs, which...
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    Labrabaco: a G7 BC calculator from Labradar tracks

    SNR is unsatisfactory, try again. I reiterate: re: "just real world data and how this works" – would you provide some "real world data" in support of your statements, or is it just a figure of speech? re: "Thus and among other things it's not realistic to derive a BC based on such short...
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    Labrabaco: a G7 BC calculator from Labradar tracks

    Sorry, this hardly qualifies as substantiation. re: "just real world data and how this works" – would you provide some "real world data" in support of your statements, or is it just a figure of speech? re: "Thus and among other things it's not realistic to derive a BC based on such short...
  14. P

    Labrabaco: a G7 BC calculator from Labradar tracks

    To start with, the purpose of the exercise is certainly not to compare data from 2 different radars with vastly different power outputs. As for the rest, this is... hmm... an interesting opinion. Would you mind substantiating any of these strong claims?
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    Labrabaco: a G7 BC calculator from Labradar tracks

    Sure! The core of it is a 3DOF small arms ballistic engine, originating with McCoy's formulas, and loosely based on old open source JBM code (heavily modified and bugfixed, especially in atmosphere and Cd curves processing bits). The main loop (cf. ebalengine.js) is numerical integration over...
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    Labrabaco: a G7 BC calculator from Labradar tracks

    Now that I think of it, there's also the temperature, that is -- speed of sound difference. In addition to the above, one would also need to multiply by the ratio of Cd of reference drag model (e.g. G7 Cd) for Mach number (real temperature) / Mach number (standard 15°C)
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    Labrabaco: a G7 BC calculator from Labradar tracks

    If you manage to get actual measured data from the FX box -- please let me know; I'm very curious to see what can be done with it (how far it tracks common projectiles, what are the noise levels, etc.). I did not have a chance to play with it yet (the box does not seem to be available on our...
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    Labrabaco: a G7 BC calculator from Labradar tracks

    Aw yeah! C++ and Perl -- stuff that God hacked the universe together with. I'm a 20th century man myself, and cordially hate this DOM/CSS/JS stuff -- oververbose, heavy, thoroughly inelegant, and crippled by design -- but nowadays it's about the only way to write something platform-independent...
  19. P

    Swiss K31: Stunning

    Great news! The export-import chain worked. Hope the mags prove up to your expectations. (I'm quite proud of the result; in our parts it quickly became the most popular K31-XXI product.)
  20. P

    a geek’s delight: reverse engineer a distance-velocity table to Cd/Mach curve

    It’s all compromise. 1. how much of a problem this is for me, personally? or, put in other words, how much of an error do I get over my typical shooting distances if I do nothing (and just rely on the vendor-supplied BC(s)? vs. 2. how much of an effort it would take me to fix the problem? In...
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