Ballistic FTE & KAC Bullet Flight Question

[jonthomps]

I have both apps for the iPod Touch and there seems to be a discrepancy between the two ballistic algorithms each program runs. I can enter the exact same data in both applications but they show different energies, bullet flight paths, mil come-up's, etc. Could someone with (obviously) a greater mind than mine please explain this?

Thanks,

Jon

 

[BryanLitz]

Jon,

I worked with Robert Silvers (developer of the KAC Bullet Flight program) on his app. I don't have the program, or any iThingys to run it, but my understanding is that he verified his program using JBM which is a correctly written solution.

Having never seen the FTE program, I can't comment on the difference(s), but I can tell you that whichever one better matches JBM is the more accurate program.

Take care,
-Bryan

 

[jonthomps]

Hi Bryan,

Thanks for the information. After reviewing both applications and comparing them against JBM's ballistic calculator the KAC software is the closest match. I'll stick with that one. Thanks again.

Jon

 

[nfhjr62]

Have Bullet Flight on my iphone and received this month two updates, the first don't rember but think was fixing some bugs and the one today was a fix for apps in meters

 

[jonthomps]

Ok, here are my findings and it's very interesting!

Below is a list of the data set constants. I set the same parameters for all three ballistics programs.

Manufacturer: Lapua
Description: Scenar (CD)
Caliber: 0.338
Weight: 300.0 gr
Zero: 100 yd
Muzzle Velocity: 2750.0 ft/s
Sight Height: 2.25 in
Line Of Sight Angle: 0.0 deg
Cant Angle: 0.0 deg
Wind Speed: 0.0 mph
Target Speed: 0.0 mph
Temperature: 59.0 °F
Pressure: 29.92 in Hg
Humidity: 45.0 %
Altitude: 7600.0 ft

Here are the results of the different software programs (at random distances) in no particular order of importance:

Ballistic FTE:
Drop (in.) Mils
800 yd -142.23 4.9
1300yd -473.89 10.1
1800yd -1096.11 16.9

KAC Bullet Flight:
Drop (in.) Mils
800yd -144.9 5.0
1300yd -488.2 10.4
1800yd -1144.9 17.7

JBM Trajectory (Simplified)
Drop (in.) Mils
800yd -144.2 5.0
1300yd -484.3 10.3
1800yd -1131.2 17.5

I hope this helps everyone make a much more informed decision!

Jon

 

[jonthomps]

nfhjr62,

Thank you for the feedback, I'll keep an eye out for updates. I'm currently running Bullet Flight 3.0.0 and I feel this app (as documented from my previous post) is a much more accurate program.