I’ve don’t have a ton of experience with ballistics apps and elevation changes, so I hope I articulate this correctly.
I went out to my local range today that has targets from 100 to 810 yards. I did surprisingly well for having never shot out to 810 yards. I was actually nailing the bulls-eye at 810 with my 280 AI and custom reloads. With that said, I used the Hornady ballistics app, but it was high at every distance. 300-500 yards I realized that I could multiple the MOA it gave me by 90% and it would be almost perfect. At 600 yards it required less correcting and I used 98% of the listed MOA, At 810 Yards I used 96% of the MOA listed in the Hornady app.
I skipped 700 yards because I don’t plan on shooting that far on my hunting trip and just wanted to see if I could hit the 810 yard target.
The Hornady app is not accurate for my setup. It isn’t horrible, but consistently shoots 3-4.5” high. The axial form factor does not let me adjust the settings enough out to 500 yards, but does correct for the longer distances. Not sure why…
I’m leaving for Wyoming next week to go on an Antelope hunt. I plan to recheck my zero at 100 yards, but not my entire dope. I’ll likely only shoot an antelope out to 400 yards max. There is roughly 7000” in elevation change between Arkansas and Wyoming. What do I do in this situation?
I used ChatGPT to help and I’ll post what it gave me in the next reply.
At 350’ in elevation and 80-90 degrees Fahrenheit My 300 yard MOA is 3, 400 yard moa is 5.25, 500 yard moa is 7.75, 600 yard moa is 11.25 and 810 yard moa is 18.25. What will my moa adjustments be when I go to an elevation of 7300 with a temp of 50-60 degrees. I’m shooting a 150 grain Hornady ELDX with a G1 BC of .574. Speeds range from 2950 to 2960 fps. Do you need more information?
ChatGPT said:
Thought for 44s
Awesome—thanks for the details. Using your baseline dope (100-yd zero assumed) and the shift from ~350 ft @ 80–90°F to ~7,300 ft @ 50–60°F, air density drops ≈17–19%. That flattens trajectory noticeably. A solid field rule is that drop shrinks by ~½ of the density change at these distances, so about 8–10% less drop at mid/long range (a bit less at 300–400). Your small MV loss from cooler temps (~10–30 fps) nudges drop up ~1% but doesn’t overcome the altitude benefit.
Here’s a practical “use now” card for your .280 AI (150 ELD-X, 2950–2960 fps):
Range
Your current MOA
Est. MOA @ 7,300 ft & 50–60°F
300 yd
3.00
~2.85 (≈5% less)
400 yd
5.25
~4.90 (≈6–7% less)
500 yd
7.75
~7.15 (≈7–8% less)
600 yd
11.25
~10.25 (≈8–9% less)
810 yd
18.25
~16.4 (≈10% less)
Notes & tips
Wind: expect ~15–20% less drift for the same wind (e.g., a 10 mph full-value hold you use now would be ~0.8–0.85× at 7,300 ft).
Your app offset: the percentage you’ve been using to correct the Hornady app should stay in the ballpark, but it won’t scale perfectly after the environment change. After you arrive, take one confirmation at ~600 yd and slightly tweak your form factor/DSF so the whole curve lines up out to 800+.
Zero & scope height: if your zero isn’t 100 yd or your scope height differs from what the solver assumes, shifts can be a couple tenths different—easy to clean up with that 600-yd check.
If you want me to tighten those numbers another few tenths, tell me your zero distance and scope-over-bore (to nearest 0.1"), and whether you true to G1 .574 or use a custom form factor already. I’ll recalc the table precisely.
Some apps, like Geobalistics which I use, don’t do elvation but instead you have to plug in temperature, humidity and pressure. A kestral supplies that data, so does this:
which is a lot cheaper.
If you’re constantly off in your DOPE, I would verify the numbers you entered for sight hight and velocity. Box Velos aren’t always what you get esecially if you’re using a 22” barrel or shorter.
Also, I know Geoballistics can do this, so maybe 4DOF will as well, but you can compensate for the difference in the app with the elvation offset.
I’ve looked at my setup numbers and inputted my velocity (reloads) based off of my Garmin. I can’t find anything that is off. I guess the ballistics app information is normally a lot closer for others??
looking though the app…I have no idea how I got 31.54 for the pressure. Didn’t check the humidity either. I assume that was populated based off other selections. I’ll look into getting a kestral or similar device, but that is out of the question for my hunt next week. Maybe better environmental conditions would have helped…maybe not.
An error of 3-4.5” is pretty small. If those environmental weren’t quite exact, that would certainly account for it. Without the need for a kestrel, you could just look up temp and humidity and altitude on Google for the day. It’ll at least be close.
Once it matches, look up the environmental you expect to shoot in and change that on the app. Then you’ll have a good drop chart.
My guess is it’s the environmentals causing the error here, but sometimes I’ve triple checked everything and just could not get the app to match real life. The axial form factor should be able to account for that 3-4.5” change. Thats a very small correction.
Just go to axial form factor > manual mode and select the correction at 500 yards
However, it is critical that this info is precise. Don’t just shoot 2 shots at 500 and say it’s high. Shoot a 10 shot group at 500 and take that average.
And when it REALLY just isn’t right, just take a click out of each distance from what the app says. Sometimes, the app is just plain old wrong.
I live close to sea level in Alaska and this comes up virtually every hunt. The apps will almost always need truing, especially past 300-400 yards. If all your data are correct, 300 and closer should not really be an issue for elevation adjustment in an app. I would make corrections in the app you have or plan to use for the DOPE you physically obtained on your range until it matches. Then when you change the elevation and temperature for hunting field condtions you are good to go. Usually, changing the velocity does the trick. But as stated above check scope height and bullet BC (maybe use G7 vs G1 model depending on your bullet type)
Hopefully, you get a shot 200 yds and closer then its not an issue.
