I drew this up the other day and printed it for my 4K wifi action camera. When shooting iron sites at the range I usually take a spotting scope with me, but it's kind of a pain to get up ever few shots to check my groupings. My new 4K action camera (https://www.amazon.com/gp/product/B01N751MXZ) has built in wifi and I can connect to it via my phone or tablet to view what it sees without having to leave my shooting position. I can even snap photos between shots to see how each placed.
This telephone post is about 250' from my shop, I had to used the optical zoom to get close up, but should be good for 100 yards.
I posted the sketchup and stl files on thingiverse if anyone is interested, if using PLA, you'll need to use some Loctite Super Ultra Gel glue to glue the two parts together.