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  1. damoncali

    Range Report Which Published Berger BCs Are From Predictions Rather than Measurements?

    I think this is just a definition/semantics thing. If you use a G1 drag function in a point mass solution, you pretty much use the Official Version of the G1. If you use a G1 BC in a Pejsa solver, and then combine it with a retardation factor or whatever it is he calls it (Pejsa isn't really my...
  2. damoncali

    Range Report Which Published Berger BCs Are From Predictions Rather than Measurements?

    Here's an idea. Why don't you modify a drag function to account for air density, and run the models yourself. Then come back and tell us the differences you find. I already know what will happen. Not because I have done it, but because, as Newton said, "I've stood on the shoulders of giants"...
  3. damoncali

    Range Report Which Published Berger BCs Are From Predictions Rather than Measurements?

    The 6DOF model does not neglect other forces. There is literally decades of research on this. What we know is that the 3DOF model does a pretty good job at approximating the overall 6DOF trajectory (excepting drift, coirolis, etc) - *when the yaw is small*. We know that that yaw is small when we...
  4. damoncali

    Range Report Which Published Berger BCs Are From Predictions Rather than Measurements?

    This appears wise. I would test any mobile solver not called Applied Ballistics against JBM before trusting the numbers. JBM is great because it offers a truckload of inputs, so you can really see what's going on. The interface to mine is very simple by comparison, and not nearly as flexible -...
  5. damoncali

    Range Report Which Published Berger BCs Are From Predictions Rather than Measurements?

    Just a nitpick, but it's an important one. I'm sure you know this, but I'll repeat it in case anyone else has bothered to read down this far. Point Mass means something very specific. Any solver that is doing the weird things that were described by mil_coder is NOT a point mass solver. It's some...
  6. damoncali

    Range Report Which Published Berger BCs Are From Predictions Rather than Measurements?

    I would pay for the opportunity to see just how bad at reading the wind I am. Sounds really cool. A few hours with a spotting scope on an instrumented range is probably the equivalent of a few months of shooting by trial and error.
  7. damoncali

    Range Report Which Published Berger BCs Are From Predictions Rather than Measurements?

    The problem I have with directionally dependent drag is that there is no physical justification for it. If there were, it would be seen in a 6DOF model, and we just don't see that happening.Of course, when you use a 3DOF (AKA point mass) simplification, you will necessarily cover over some stuff...
  8. damoncali

    Range Report Which Published Berger BCs Are From Predictions Rather than Measurements?

    If you believe that the bullet generally aligns to the air flow and that any minor yaw is accounted for by BC, then yes. In fact, if you want to argue that wind should be dependent on some sort of sideways BC, you must also argue that drop is subject to the same phenomenon and we're back where...
  9. damoncali

    Range Report Which Published Berger BCs Are From Predictions Rather than Measurements?

    That's why I said "in theory". Just explaining the way the model *has to* work. You can't separate wind and elevation with point mass unless you manually add some kind of factor in, in which case, it's no longer the point mass method - it's something else.
  10. damoncali

    Range Report Which Published Berger BCs Are From Predictions Rather than Measurements?

    The point mass method, correctly implemented, does not differentiate between windage and drop - it just calculates x, y, and z of each step of the trajectory. There isn't a separate wind calculation. Changing the BC will necessarily change both drop and windage. In theory, if you improve one...
  11. damoncali

    Range Report Which Published Berger BCs Are From Predictions Rather than Measurements?

    I'm not suggesting that you need 6dof for every shot. I would say that trying to make BC a function of multiple interdependent variables is a fools errand, and is exactly why the 6dof model exists in the first place. When you make the BC dependent on sg, twist, velocity, and more, all of which...
  12. damoncali

    Range Report Which Published Berger BCs Are From Predictions Rather than Measurements?

    There is a reason they came up with the 6DOF method and did all that work to figure out all those coefficients. It's because a single coefficient is incapable of capturing all of these dependencies. Your BC becomes a variable dependent on many other variables. The next thing you know, you need...
  13. damoncali

    Range Report Which Published Berger BCs Are From Predictions Rather than Measurements?

    I think it's strange that you're picking on Berger, who of all the makers has gone to pretty great lengths to give us accurate numbers, and the only bullet maker to make detailed data available (via Bryan's book) on what those measurements are comprised of. Heck, Sierra still publishes velocity...
  14. damoncali

    How many sheets of printer paper between floated barrel and stock?

    Any movement from heat is going to be way less than the movement from vibration/recoil. A dollar bill isn't enough to prevent contact, and it's not a given that contact is bad. We float barrels so we know what we're getting - no contact. If there is contact, and it changes, it throws another...
  15. damoncali

    F T/R Competition Single Shot Action vs Repeater Action

    There is no such thing as a barrel that is too heavy for the action threads. The preload on the barrel threads is thousands of pounds. The barrel is about 6 pounds. It's just not an issue. As for the original question, there is no benefit to a repeater in F class since you load single shots...
  16. damoncali

    Range Report Cortisol is and spin drift .308

    There's actually a section in McCoy's book that details how the curvature of the earth impacts the solutions (which assume that the earth is flat). It's a bigger number than I would have thought. I want to say about an inch of error at 1000 yards, but I'd have to look it up. The application...
  17. damoncali

    Range Report Cortisol is and spin drift .308

    If you really mean "complicated" (as in you have the equivalent of a math or engineering degree), then check out Bob McCoy's book, "modern exterior ballistics". It is THE book on ballistics. Litz's book is by far the best of the bunch for people who prefer to skip the math.
  18. damoncali

    Rifle Scopes Is Glass quality Bullsh*t? Or is it me?

    You sort of answered your own question - and you're not alone. The difference between $400 and $2000 glass is noticeable to me at high magnification. That said, the difference between $1000 and $2000 is not. To each his own. So, yes, "Glass Quality" is in my view largely BS. I'm not saying...
  19. damoncali

    F T/R Competition 208G AMAX & 210G Berger Touching Lands Measurements

    I don't know, but if you don't already have those other bullets, Bullets.com has the 210 VLD's in stock. Bullets.com
  20. damoncali

    F T/R Competition Build my F-T/R rifle & Loading System

    I use a Barnard (two-stage) set at more or less 10 oz. I think it's fine. It's not hard to hold a 18 pound rifle on target while prone, so triggers aren't that important so long as it's decent.
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