Originally Posted by Yondering
Originally Posted by Jordan Smith


Absolute pressure refers to whether you're entering the actual air pressure compared to a vacuum, or if you're entering air pressure corrected for sea level. If you're located a few thousand feet above sea level, and you see a reading of 29.92 InHg, then you're reading relative, gauge, or barometric pressure. If you look at your Kestrel and see a reading of 25.62 InHg, then you're reading absolute pressure. Absolute pressure read off of a handheld device is preferred, as it bypasses conversions and local weather station input. FYI, if you have an iPhone 6 or newer, your phone has an air pressure gauge built in, and you just have to get the "Barometer" app to get absolute pressure readings from your phone without having to use a Kestrel or similar.

Enable Zero Atmosphere means that your app will compare your current shooting atmospheric conditions with the conditions present when you zero'd the scope with that load, and will calculate the difference in your zero for use in your current shot solution. If this is clicked off, the app just leaves your zero the same for any atmospheric condition.

I use Ballistic:AE instead of Shooter, so I'm not 100% sure, but I'm guessing that MV variation is a measure of the temp sensitivity of the powder you used in your load, and how much the MV changes for each degree F in temperature change.


Jordan, have you been able to get Ballistic AE to use the iPhone internal barometer and gps for measurements instead of looking for data from a local weather station? I thought it was supposed to per the literature, but with cell and wifi turned off to test it, it fails to populate any weather data on my iPhone 6s. I only just downloaded Ballistic AE a few days ago though so I may be missing something.

I know the sensors on my phone work fine because Strelok does use the internal barometer and GPS, although I don't like the app layout as much.

As a side note, a handy iOS app I discovered recently is Density Altitude+; it's a very simple app that calculates density altitude from the device sensors and a temp input, which defaults to a local weather station but can be manually adjusted too. Well worth the $1.99 for the app.


Thanks for the tip on the Density Altitude app, I'll check it out.

The GPS doesn't get used to populate weather data, IME, but the barometer does get used to populate the absolute pressure box. Sometimes you have to click the "get weather" button, then click on the pressure box specifically for the measured pressure data to appear. I thought it was just a glitch that sometimes happens with my particular phone, but it might be more broad-based than that.