Ballistics Apps and Scope Zero

[stoky]

On measuring, I gotta go with Bart. You can easily eyeball to 0.1 inches holding a ruler up from barrel to scope center.

If you want to be more accurate than that, put the rifle on a surface plate and use a height gage

........or a laser interferometer, with a transfer punch in the chamber with the pointy end sticking out

 

[Bart B.]

Ballistic software typically uses sight height calculated as the distance from muzzle center up to the line of sight above the muzzle.