For years I have been using the Nikon spot on app along with my Nikon bdc scopes. It has worked amazing. The app will calculate drop for a bullet with a few pieces of information. They have thousands of bullets for almost every caliber. I have used the app to print out ballistic tables for my rifles so I know hold over for different ranges. Well now that Nikon is no longer making scopes I have to change to a different brand. Does anyone know of an app/scope combo that does this?