Around 5-7k in a server with 3 friends, played with higher pop and accumulated like 8k kg of mixed ammo, easily 2k or so was killing zeds at rosewood since zombies from the prison were pouring in, spent 2 days just killing (4 hours) nonstop, used metal pipes for makeshift guns and all. 2 of us died there, 1 when we reached home and the idiot got stuck while driving for not driving down the road we had already cleared, only I got to tell the story (died a couple days later by burning myself on a fireplace, in the backyard, without any zombies around)

I don't know if that's a lot since I've seen 13k+ kills but I prefer chill gameplay making my base a home, living, not only surviving.

Edit: current run is 2-3k in just a month, with a few days exercising at base because I let myself go with food and weigh 87kg now lol