Longest Sniper Kill

I've done 1029, but I've seen someone do 1052

685 

Yeah I get that for the zeroing however is this the highest kill recorded so far as I’ve seen like 300+, 400+ ? 

I was using a sniper rifle today and noticed that the zeroing effect ranged from 100, 200, 300, 400, and 500 meters.

So, no, I don't think 511 meters isn't an  excessively long shot since an adequately accessorized sniper rifle could indeed shoot that far.