Applied Ballistics for iPAD giving strange numbers?

[jlow]

I am wondering what I am doing wrong. I put in two rifles and two loads and compared the numbers to my Kestrel AB for the same things.

The .260 load for a Berger 140 Hybrid MV=2795 fps was slightly different 3.4 Mil (Kestrel) for 600 yards shot compared to 4.0 Mil (AB App).

The .223 load for a Nosler CC MV=2753 fps was significantly different 15.13 MOA (Kestrel) for 600 yards shot compared to 30.75 MOA (AB App).

Having experience shooting both at that distance, I am sure the AB App data is way off, especially the .223 load. Here is a screen shot from the iPAD for that load. Using G7 data for both but drag curve data for Kestrel. Anybody know what the problem is?

BTW, I can see that the screen dump I put up says 2087.0 fps, but when I check back in the “Add Ammo” area, it does say 2753 fps – so another mystery?

On the same note, I check the .260 data and found that although I input an MV of 2795 fps, the HUD shows 2597 fps? What's the deal?

Just an update, I find that if I calculate the difference between what I entered and what is in the HUD i.e. 666 fps or 198 fps to the original numbers i.e. 2753 and 2795 to get inflated numbers i.e. 3419 and 2993 fps, putting the new fudged number in the "Add Ammo" area will in fact give me the correct fps and dope in the HUD. So the question is why is AB arbitrarily taking these numbers from my MV?

 

[bohemR13]

Do you have the angle inclinometer sync turned on within the app? I don't know if the AB App has it but in SHOOTER there's a way to have the program pull data from the internal accelerometer pull data for inclination/declination between the shooter and target.

When this happens and you are looking at the phone in front of you the solution comes back with insane numbers because of the way you're holding the phone in your hands.

Looking at the numbers for the 223 solution at 30+MOA it reminds me of this problem when a buddy of mine ran into the same thing with SHOOTER.

 

[DocUSMCRetired]

From the looks of things, I think you have input a number in to the MV Variation incorrectly.

MV Variation is FPS per Degree. For instance, the change from 100 degrees to 60 degrees is 20 fps. Then the correct input is .5 MV Variation.

Also scope correction factor, it should be 1 not 0 just incase.

www.abmediaresources.com/ABApp.htm Some good reading.

 

[jlow]

Doc - Good info thanks! That is exactly right, for some reason I thought that number related to ES and so entered a relatively large number. I inputted the 0.5 MV number you suggested and now the numbers are much more reasonable – THANKS!

bohemR13 – thanks for your input but Doc is as usual right on target!

 

[jlow]

Having discovered this "problem", must say that is a very nice feature to have being able to adjust for temperature!