LoadBase 2.0 Question

Discussion in 'Rifles, Bullets, Barrels & Ballistics' started by woolecox, Jul 1, 2009.

  1. woolecox

    woolecox Well-Known Member

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    Any LoadBase 2.0 experts out there?

    I just fired off an email to Patagonia Ballistics. There are no support phone contacts that I could find. Here is a copy of the email I sent. Perhaps someone here has an explanation. Thanks!

    "I installed your program on my desktop at home and so far have been pretty impressed and satisfied with the program. I would like to know if I can also install the program on my laptop as well. Can I do this under my current license agreement? If so, How?

    Secondly, if I read your documentation correctly, the mathematical model of this program does not use the normal G1 Ballistics Coefficient (BC) that is so commonly listed with most bullet manufactures. I understand that the program uses a parameter called Drag Coefficient (DC) to make ballistic calculations. So how do I arrive at this Drag Coefficient needed to calculate ballistics for a given load? Again, if I read your documentation correctly, this involves taking a series of four velocity measurements over incrementally increasing distances to a point where the projectile is just above supersonic velocity.

    Does this mean that I need to set my chronograph up at increasing distances on the range and shoot through it? This is impractical/unsafe on the range and impossible at most ranges. A 7mm Remington Magnum is still well above supersonic velocity at well over 1000 yards! I am confused. Please explain.

    This would be a lot easier to figure out if I could speak to a real live human being. Please feel free to call me.

    Thanks,
    Steve"
     
  2. woolecox

    woolecox Well-Known Member

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    Well, apparently not. but here is the reply I got from Patagonia Ballistics:

    "The License agreement allows for two licenses (included in the price) one for the Desktop and one for the Mobile edition.

    However, if you prefer to exchange your Mobile license for another Desktop, no problem at all, just let us know.

    On the other hand, if you want to install more licenses (than the two already included), then you need to purchase another one.

    The Registration process must be run on any new device, since the locking mechanism is device-specific.

    You are right, LB ballistics engine uses an advanced drag model, that’s not based on “G” functions, meaning for example, that there is no need for a G7 BC that lately has been so hyped.

    However, the program uses as a starting point, and for the best convenience due to its wide availability, the G1 BC.

    In general terms, a DC=0.500 is a very satisfactory starting point for streamlined bullets, provided that the BC is of good quality, meaning it’s correct and from a serious source.

    As stated in the User’s Manual, any method not based on velocity readings (taken by a chrono) is not recommended at all, and by the same token also applies to BC calculations.

    Since the right way to compute a DC values is somewhat difficult to accomplish, the best recommendation is to play with the DC value until a match is registered against your drop values.

    But, as said before, the default value should give you plenty of accurate results, within a 96% confidence level under most situations.

    Best regards,

    PB

    PS: We tried to keep to answer as practical as possible, if you need more details, please do not hesitate to contact us as required."
     

  3. kcebcj

    kcebcj Well-Known Member

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    Patagonia’s licenses policy has kept me from purchasing the software. Just too restrictive at this point in time at least for me.
     
  4. woolecox

    woolecox Well-Known Member

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    They promptly sent the key to unlock my laptop and I installed it without a hitch. So now I can run it on two computers. That is the limit of their license.

    It is leaps and bounds better than any other software that I have used to date. It is a little pricey but at least you get two license and very good support. They will get back to you same day if you have a question.

    Good luck!
     
  5. bigngreen

    bigngreen Well-Known Member

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    There support is great, I think doing the tech support through the e-mail allows the most direct answer.
    I'm shooting 140 gr .277 Bergers and using there BC I'm running the drag @ 651 to match my drops to 1015 yds.
    140 gr .277 Accubond I run @ 500 drag and that matches my drops.
    I've made a 3/4 in plate steel that I can shoot over and set the crony behind it, I'm hoping to get out and use Loadbase to get the calculated drag.
    It is amazing to use, I'm really just learning to use it. Excellent value!!!!
     
  6. phorwath

    phorwath Well-Known Member

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    I need to get a steel plate for chrono protection also. Shot over mine at 990 yds without any shielding and it turned out OK but I didn't like it. Steel plate or some other protection in front of the chrono/skyscreens is the only way to do this at long ranges, unless you're a natural born gambler.
     
  7. mattj

    mattj Well-Known Member

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    I've shot over my chrony out to 200 yards to calc the DC values, and it really isn't as scary as it sounds... even if you or your rifle can only hold 1 MOA on that day, that's only a 2" group -- plenty of room to avoid your skyscreens. If you're at all nervous about your dope, put a second target out there to verify your zero before you move over to the target behind the chrono (also, a CED M2 is nice, since the expensive part doesn't have to be near the target). Remember to give plenty of time for the barrel to cool between shots -- try to get in all your shots at the four different ranges in while the environmental conditions are the same -- and use the average of a bunch of shots to help get 'good' data (of course, if your load has low ES/SD, your data will be better).


    When I don't have the time/motivation to use the chrono method, I've had good luck using the JBM online calculator with the G7 drag function for the particular bullet -- I then enter all of the same data (except G1 BC and .500 to start) into Patagonia Ballistics and tweak the DC until things line up. I've been able to get the dope to match at every 100 yard increment out to 1000+ yards using this method. I then use that DC value with PB on my Pocket PC to adjust for conditions in the field. Seems to work pretty well.

    Tweaking the drag function to match your known dope is one step better if you have really meticulous field data on your real-world drops (including environmental data) -- but the chrono method will generally yield the best data.

    Remember, garbage in, garbage out!
     
  8. woolecox

    woolecox Well-Known Member

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    Thanks for the advise guys. Really appreciate it!

    Wooly