Recent Posts

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General discussion / Re: Problem downloading
« Last post by admin on January 21, 2019, 11:29:11 AM »
try again?
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Updates / Site problems solved and a new version of BfX
« Last post by admin on January 03, 2019, 04:16:41 PM »
A happy new year!

I have solved the problems with my servers certificate and now bfxyz.nl is not regarded as a bogus site anymore. 8) Furthermore I have recompiled bfx, so that the software includes the latest upgrades from Microsoft. I also have upgraded the simulator "what do I shoot today". You find the simulator at the bottom of the download page. The simulator is able to simulate a multi target (at multiple distances) match under various range, wind and wind fluctuations ammunition/gun and shooter accuracies. Helas, depending if you run the 32 or 64 bits version of Excel, one has to change the visual basic code to point to the file locations where the bfx.xll and bfx64.xll can be found. Unless you store them as C:\bfx\bfx.xll or C:\bfx\bfx64.xll.

Personally, I use this spreadsheet a lot. Soon to see how much points I gain in typical Dutch rifle matches at 100 and 300m if I upgrade my barrel to a more accurate one. As I am a quite able shooter with the service rife (3rd in the National Championships 2018 @ 100m, 2nd at 300m) and the competition is fierce, an additional point from the accuracy is welcome.
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General discussion / Problem downloading
« Last post by ms504713 on April 21, 2018, 06:41:04 AM »
When I attempt to download the application zip file, I receive the following message: "Forbidden - You don't have permission to access /cgi-bin/bfxdownloader.pl?file=bfx64.xll on this server." I am using a Win 10 computer.  I have tried to download using Edge, IE, Chrome and Firefox all with the ame result.  Anyone have a suggestion as to how I can remedy this problem?
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Updates / bfxyz.nl now fully supports SSL
« Last post by admin on March 27, 2017, 12:05:39 PM »
The site is now only (and automatically) accessible through SSL. You will see https:// (instead of http;//) in the address bar of your browser. Https, through the use of SLL, would make the use of websites secure and private to use.  SSL is used by https as in: https://en.wikipedia.org/wiki/Transport_Layer_Security
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Worksheets / launch angle
« Last post by admin on February 11, 2017, 12:19:58 PM »
Hello,
straightforward computation of trajectories and launch angles (elevation) for two bullets with different bc zeroed at same target
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Updates / BfX is recompiled
« Last post by admin on January 13, 2017, 06:10:03 PM »
Happy 2017  with the recompiled version of BfX!
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Updates / Error
« Last post by admin on January 05, 2017, 10:18:37 AM »
Happy 2017.
Something went wrong with the forum. Helas. I had to install the backup of january 2016.
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Ballistics / Re: Pejsa and 3DOF PM
« Last post by admin on December 09, 2015, 11:00:26 AM »
I would like to add a speculation,

given the purpose of Pejsa's applications in AA guns he probably has some formulas that work for large elevations too.
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Ballistics / Re: Pejsa and 3DOF PM
« Last post by admin on December 08, 2015, 02:41:47 PM »
the effect of the flat fire approximation is that it simplifies the math.
That is why Pejsa is able to give formula's.
Formula's can speed up the computation quite a lot - and could be programmed in the computers of the early sixties

BfX, due to the flat fire formula's can be used to 15 degrees.
Due to progress in computing, however, PM can be done at an instant, compared to the early sixties
In priciple I can switch BfX to point mass as I already have the technology to do that.
yet I do not want to support applications that go beyond 15 degrees - these have nothing to do with target shooting
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Ballistics / Re: Pejsa and 3DOF PM
« Last post by 375CT on December 07, 2015, 11:17:45 PM »
Pejsa makes two assumptions to derive his formulas:
1) at a given mach interval the drag function can be approached by a power of the mach number g(m)=a*m^b a and b are real numbers. With the custom drag funtions BfX determines for each interval a and b. Then applies Pejsas method. Numerical integration assumes a constant drag value for a given interval.

2) a flat fire approximation

ad 1) if the  mach interval is small enough Pejsa method, and the software has to sum the effects over many intervals, Pejsa method becomes is equivalent to a numerical integration, probably equalling the accuracy of a  runge kutta integration. BfX has the ability to use a measured drag function, e.g. the ones of lapua. BfX results matches here  the ones of a 3dof model, see the workbooks mman posted.

ad 2) a 3dof is able to go beyond the flat fire approximation

BfX is all about generating tables. However, Pejsa publishes many simple formulas which one can use with an electronic calculator are sufficiently accurate for most purposes. In that case it is much faster than 3dof.

Robert, thanks for the reply. But how would you compare Pejsa with PM beyond the flat fire approximation and the treatment of drag? I understand that BfX has many improvements over the traditional method. Perhaps I haven't got a full grasp of your text.
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