GeoBallistics vs AB output…. WTH?!

[category_theory]

Ok. So I use GeoBallistics and wanted to try out AB…. I input the same parameters and everything into both apps. I then check to see the solution for a 1400 yard shot. The solutions are so far off it’s insane! I must be doing something wrong here and probably on the AB side…. Screen shots attached.

I am shooting 140 gr Berger hybrid targets at around 2861 ft/s. GB says U8.87. AB says U14.5!


WTF am I doing wrong?!

 

[6.5SH]

With sea level and your numbers in GeoBallistics I get 13.6 mils for 1400 yards on Android.

 

[category_theory]

With sea level and your numbers in GeoBallistics I get 13.6 mils for 1400 yards on Android.

With 4DOF I get 10ish…. What BC are you using? G1 or G7?

 

[6.5SH]

With 4DOF I get 10ish…. What BC are you using? G1 or G7?

The 0.311 G7 in both your pics.

FWIW AB using their lower measured G1, G7 and custom curve all give a 14.x mil answer.

Having the rest of your data would make any comparisons more accurate.
Examples; I doubt your scope height is really 1.5", what environmental data are you entering and how is it gathered? Have you actually shot this and had it line up with any prediction?

ETA:
4DOF with sea level and your info also gives 14.54 Mils for 1400 yards
If I do something like 13,200 feet elevation it goes to 10.61 Mils, my guess is your environmental data is wrong and inconsistent among each app.

 

[category_theory]

The 0.311 G7 in both your pics.

FWIW AB using their lower measured G1, G7 and custom curve all give a 14.x mil answer.

Having the rest of your data would make any comparisons more accurate.
Examples; I doubt your scope height is really 1.5", what environmental data are you entering and how is it gathered? Have you actually shot this and had it line up with any prediction?

ETA:
4DOF with sea level and your info also gives 14.54 Mils for 1400 yards
If I do something like 13,200 feet elevation it goes to 10.61 Mils, my guess is your environmental data is wrong and inconsistent among each app.

I reset my environmentals and it’s ok now….. . Thank you!

 

[rijndael]

Having the environmentals get changed to something crazy, making the come-ups crazy low, has happened to both me and my shooting buddy. There's something buggy there.

 

[category_theory]

Having the environmentals get changed to something crazy, making the come-ups crazy low, has happened to both me and my shooting buddy. There's something buggy there.

For real! I hadn’t done anything to the environmentals since my last outing which was pretty tame as far as weather goes…. Either way thanks y’all for the help!

 

[category_theory]

So question for folks and following up. All environmental data being the same and using the same g7 BC stats GeoBallistics and AB are still roughly 0.11 mrads apart…. With GB being higher…. Was curious if others have seen the same. I would assume they are using roughly the same engine for firing solutions and with all factors being equal that they’d be closer…. Or the same I guess…

 

[6.5SH]

So question for folks and following up. All environmental data being the same and using the same g7 BC stats GeoBallistics and AB are still roughly 0.11 mrads apart…. With GB being higher…. Was curious if others have seen the same. I would assume they are using roughly the same engine for firing solutions and with all factors being equal that they’d be closer…. Or the same I guess…

0.11 is one click of difference and a prediction at that. You'd true up either of them to match what your rifle actually does.

 

[Tokay444]

So question for folks and following up. All environmental data being the same and using the same g7 BC stats GeoBallistics and AB are still roughly 0.11 mrads apart…. With GB being higher…. Was curious if others have seen the same. I would assume they are using roughly the same engine for firing solutions and with all factors being equal that they’d be closer…. Or the same I guess…

Which one is correct?

 

[category_theory]

0.11 is one click of difference and a prediction at that. You'd true up either of them to match what your rifle actually does.

No I get that…. My questions was more to where the error or delta propagation comes from bw the models…. Was just curious if anyone knew.

 

[Tokay444]

Which one is right?

 

[kthomas]

Unless your 6.5mm identities as a .300NM shooting high BC solids, there's no way it's only 8.87 mils to 1,400 yards...

 

[Redbone374]

I noticed your bullet length is different between the two apps also.

 

[DocUSMCRetired]

From what I can see here you have a couple of things different in the inputs.

1) The Firing direction on the AB App is 90 degrees with a latitude of 37.9 deg. The firing direction on the GeoB is 336 degrees.
2) The wind on the AB App is 10mph at 90 degrees, while in GeoB you have the wind at 188 deg and 6.2 mph.
3) The impact velocity and kinetic energy on AB is 1133fps and 339 ftlbs while on GeoB it is 2215fps and 1525ftlbs. This is a huge difference.

Something is very wrong with your GeoB inputs. A 338 Lapua 300gr with a G7 of 0.414 at standard sea level atmospherics has 10.5 mils of hold at 1400 yards. I would venture to say that your 6.5 with 140s shouldn't be out performing a 338 at 1400 yards.