This app is great. Works for any caliber, any distance, any target, and it’s easy to use when you get the hang of it. I found the app works best with printing my own 8.5” x 11” targets that map to the A-25 specs @ 100yds—the distance I do most of my indoor practice. After the range, I scan my sheets on a flatbed scanner, transfer images to my phone, and then use the app—sounds complicated, but it’s easy and fast. Love being able to assess and adjust a zero in a scientific way. Also good for tracking progress and training. Overall, LOVE this app, highly recommended.