I had one in Germany, because I was in a hunting area that actually had a big open feild about 1IK square, and I suck at distance guessing.
I couldn't find any to scale maps of the area, so I ordered the 400 RANGEFINDER from Cabela's to me in Germany, and the postage alone wiped me out (this is when these puppys were expensive).
The first thing the directions said to do was FIND SOMETHING THAT IS EXACTLY 50 YARDS AWAY TO CALEBRATE.
That's why I got the danged thibg in the first place.
So I found a soccer field in the town I live in (not a hard task in Germany) and would half the distance and do meters, and tried to do the calebration thing there, only to learn the field was a junior field of only 80m
But any way, a long story short, they do not work for rifle shooting hunters, I have been told by short range bow hunters they 'can work' but he hated them.