OneZero Ballistics Calculator

OneZero now uses your compass for wind. • Use Current Weather now fills in the direction the wind blows from as well as its speed. Tap Target Direction, point your iPhone at the target, and OneZero works out the wind's clock direction. You can still pick it by hand. • On Apple Watch, each round's windage hold now sits under its elevation hold and follows the watch's compass, so you can face the next target and read the hold. The info button moves to the bottom-right corner. • Headwinds and tailwinds now count too. They change the drag, so the drop: a 20 mph headwind lowers a 220 gr subsonic round almost 2 inches at 300 yards. • Coriolis: with your latitude, which Use Current Weather fills in, holds include Earth's rotation, about 3 inches each way at 1,000 yards at 45°. With the target's direction they include its vertical part too, and on Apple Watch they follow the way you face. • Stability now accounts for muzzle velocity and air density, as Miller's rule intends. Subsonic loads read less stable than before, with less spin drift, and thin air at altitude steadies a bullet. • 139 cartridges, up from 66, and 4,266 factory loads, up from 3,891. • About 500 more factory loads now include bullet length for stability and spin drift, and about 250 more have a G7 ballistic coefficient.