iPhone and iPad install web apps from the Share menu:

This link opens the calculator with both profiles, the environment and the chart range exactly as they are now. Units follow each viewer's own setting.

Enter the elevation you actually dialed at a known distance. The solver finds the muzzle velocity that produces it, using this profile and the current environment, so set the environment to the conditions when you shot.

Hang a tall target with a plumb line. Aim at the same point for every shot: fire a group, dial up a known amount, fire again, and measure how far the group centers actually moved along the line. Tracking is the measured move divided by the dialed one.