I just make a video-call between two cell-phones; works great. - Requires of course phone-coverage and generally the phones need to be connected to powerbanks. - and if you are not too cocky about your shooting skills you should have some kind of protection in front of the phone at the target...
View your targets from a distance using WiFi or cellular network
play.google.com
Wasn't happy with the image quality of video calls when shooting paper targets and this app solves it for me. Also data usage is lower compared to video calls (especially in photo only mode). Works at any range provided there's phone coverage (WiFi options are available but didn't test them).