For the purpose of this question I input the exact same data in all 3 shooting app: Bullet type, weight, barrel twist, zero, scope, weather.... same data all apps.

The apps that I used are the Strelok Pro, Hornady BC Calculator and Vortex Long Range Ballistic Calculator(my scope is a Vortex).

What I have found is the Strelok Pro does not allow for altitude the other two apps do allow for altitude to be input. Strelok web page says that as long as I enter pressure, humidity and temperature that is enough to account for the altitude. It must be because the MOA corrections for all 3 apps almost identical at all the yardages, I adjusted the altitude on the other 2 apps one was at 600 feet and one at 4000 feet.

So if you can only input one data point, altitude or weather conditions which one would you use and why?

The other thing I observed and it caught me off guard is that the MOA adjustments for elevation calculated in all 3 apps is not that big of a difference shoot at 400 yards at 600 ft elevation versus shooting 400 yards at 4000 ft elevation. Vortex said add 6.1 MOA at 600 ft elevation and 5.9 MOA at 4000 ft elevation. Don't know why but I thought there would be a larger spread in the MOA between the 2 altitudes.

I would put in the exact weather conditions you are shooting in, which should include your pressure. If you don't know your pressure, you can come close to calculating it based off your altitude and standard pressure at ground level. The most important weather inputs are your temperature, pressure, and altitude (the humidity is a factor, but not much of an influence). But you can calculate your pressure based off your altitude from a ground level pressure. As you go up in elevation, your bullet has less drag, and will drop less, requiring less come-up. When we go shoot in the canyons of West Texas, we are around 1800 or 2500 feet. I enter all my exact weather data into my ballistic program for shooting out to 1700 yards. I pull up the closest airport to get the local data and use that. My buddy also runs a Kestrel, and that data is often the same, or very close.


https://www.omnicalculator.com/physics/air-pressure-at-altitude

Temperature and Barometer ar what I would use if that is all that is available. Density Altitude and temp is what really affects trajectory. But barometer is a way to get there.

400 yards and less you are not going to see huge changes in elevation corrections, with density altitude changes.