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Computerized Ballistic Solutions

 
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Old 10-22-2003, 12:02 PM
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Computerized Ballistic Solutions

I'm getting frustrated. I would like some feedback on this idea, but after posting this on another forum got practically zero response. Let me give it a shot here.

There are a couple of companies that have ballistic software on a PDA for use in the field. I bought the Horus product but found various drawbacks and decided to write my own. The problem I had with the Horus was that the firing solution was simply in terms of MOA. What if you wanted a MIL solution? What if you wanted the solution in terms of your particular scope turret?

This is a screen shot of a 1000 yd. solution where wind is at 4 mph from 220 degs and the target is moving at 3 mph at 80 degs relative to the shooter. The solution shows windage in both MOA and MILS, a lead MIL value (which deals with the target's motion) and a "Holdoff" value with combines both windage and target lead.



Note that in the window labled "Turret" is the result "33 - 2". This is the elevation correction of 29.1 MOA in terms of my particular scope turret: turn the turret to "33", then back off two clicks. The reason that this readout is valuable is that on my particular scope, although each click is supposed to equal 0.500 MOA, in fact each click equals 0.451 MOA. So the turret readout converts the elevation correction to my turret scale at a rate of 0.451 clicks per MOA and then tells me what the setting is based upon the scale on my turret knob. This firing solution is based upon the following preset values:



By way of another example, lets say that I put another scope on my rifle and this scope has a BCD that is set up for a .308 Win, 168 gr. bullet. From the setup, you can see that I am shooting something more akin to a 300 WM (actually, a 300 WSM.) Usually, a BDC for the wrong bullet is useless. However, in this screen shot I have had the program output the turret information in terms of the .308 BDC scale.



The program is telling me to set BDC on '900' then back it off three clicks. So, even though I've got the wrong BDC, the program can still use the scale for a different bullet and muzzle velocity.

I'd like any feedback you guys may have concerning this type of output and your thoughts as to how usable this program might be.

Thanks.

[ 10-22-2003: Message edited by: Blaine Fields ]
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Old 10-22-2003, 12:54 PM
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Re: Computerized Ballistic Solutions

I've got to run right now but it looks interesting, I'll have to read through it when I get back from the range, got to run. [img]images/icons/smile.gif[/img] I'm always up for another PDA ballistics program. Does it have different drag models, G5, G7 etc?
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Old 10-22-2003, 03:50 PM
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Re: Computerized Ballistic Solutions

[img]images/icons/confused.gif[/img] [img]images/icons/confused.gif[/img]
The Horror ballistic program, oops I mean Horus ballistic program is just plain awful. End of story!!

They use something called a C1 drag model. I have found no mention of this drag model in any of my ballistic books. Iíve sent them 3 emails asking them what calculations they are using and how you convert a G1, G5 or G7 BC to their C1. Iíve never received a response. I did down load their trial ballistic program and gave it a test drive. This has got to be one of the worst written ballistic programs ever. I pulled out my scientific calculator and took the sample bullet profile on their program and used the 100 year-old G1 drag model to see if that was what they were using. Guess what?? My calculations matched the programs exactly. Their advertised state of the art program is based on 100 year-old calculations for a 1 pound one inch round artillery shell. WOW, how accurate do you really think thatís going to be!

Think of it this way. According to their ballistic program, all flat nosed, spire point, boat tail, and VLD bullets all have the exact same aerodynamic flight characteristic. There is no way to change drag models with their program. All bullets are treated and calculated the same.

Save your money on this one folks. If you want the best ballistic program written, invest in the RSI Ballistic Lab. The calculations used in this program are the exact same calculations used by the US Army at the Aberdeen Proving grounds.

And do your self a favor and stop using the G1 drag model in your current ballistic programs for your calculations. Use the G1 for Standard Flat based bullets, G5 for standard boat tail bullets, G6 for Spire Point Flat based bullets and G7 for VLD bullets.

Hope it helps

[ 10-22-2003: Message edited by: Jeff In TX ]
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Mathew 5:16

Distance is not an issue, but the wind will make it interesting!
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Old 10-24-2003, 02:25 PM
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Re: Computerized Ballistic Solutions

<BLOCKQUOTE><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><HR> Hope it helps <HR></BLOCKQUOTE>

Actually, it doesn't. I am extremely satisfied with the accuracy of the drag functions I am using. My questions had more to do with whether a real-time program should have windage output in terms of both MOA and Mils and include lead and holdoff values.

My next question had to do with the value of output in terms of the scale on the shooter's scope.

If you have any comment on these issues, I would appreciate reading them.
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Old 10-24-2003, 02:39 PM
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Re: Computerized Ballistic Solutions

I really like the Exbal program!! I took a big 4 point buck with it yesterday at 823 yards.

It will do mil's and MOA and the PC version will let you put any value in for your adjustments.
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Old 10-24-2003, 03:39 PM
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Re: Computerized Ballistic Solutions

Blaine,

I think Jeff was just trying to emphasize the importance of A PDA program having the correct drag functions for the bullets we use, the G1 is not that. It works OK but, so does using MOA in you mildot scope, you're just always comprimising. To me, the mil data just isn't important, tho I never use mildots and that's why it isn't.

Exbal is the best PDA program on the market in my opinion, but it still offers no other drag curve other than the G1 to keep a guy on target at BOTH 500yds and 1000yds. You give up accuracy at one range to gain it at another because the drag curve doesn't ever match the form of the bullet being used, it's the basis for the form Jeff mentioned.
Take it or leave it, but it's true.

If you want to create a program with mils, I'm sure a bunch of guys would thank you for it and maybe more are even interested in that as a priority, while a sacrifice in the accuracy of the program isn't. For most guys that never really shoot past 6-700yds the G1 may be fine, so you have that on your side. [img]images/icons/smile.gif[/img]

When Jim at www.shootingsoftware.com makes the program for a PDA it will blow any on the market right out of the water, as I'm sure it will at least have the G5 and G7 curves, and may also have a custom curve based on the form factor from the exact bullet of your choosing like his RSI Shooting Lab program allows you to create from your bullet dimentions.

Right now, IMHO Exbal looks simpler and easier to understand than the windows that you posted here. Exbal is also very flexible and has a customizable BDC analysis and solution in either MOA or MILS that works very well. Good luck with yours too! [img]images/icons/smile.gif[/img]
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  #7  
Old 10-24-2003, 03:41 PM
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Re: Computerized Ballistic Solutions

SR90, congrats on the buck there too!! [img]images/icons/cool.gif[/img]
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