I bought a Bushnell 600 about 10 years ago, it works good out to 300+ yards (white painted steel) but I haven't been able to get anywhere close to 600, at our property we set the targets up at 100, 200, 300 and then set up longer targets from the 300yrd spot, for hunting I mark distances before hand and mark with streamers but anything over 300yrds is extremely rare (most inside 100yrds), the 600yrds is from a "reflective" surface and probably 1/2 that is what it is good for. I bought my grandson a rangefinder from Amazon rated for 800yrds, I haven't seen it work yet but he loves it for golf.