Zastava M85 Stutzen stock in 7.62x39.
Solid, rugged, reliable, lightweight, accurate enough for "Zombie Kill Shot" well past 100M with open sights (zombies further than that you can just walk away from).
x39 used to be a "big box and surplus dealers only" ammo, but I can't remember the last time I was in even the smallest of small town gun stores that didn't have crates of surplus and crates of hunting loads in stock.
I would take the Zastava over the CZ (which is overall a more refined rifle) for one simple reason: Internal drop floor magazine. In the ZomPoc, I wouldn't want to worry about dropping and losing a magazine in the dirt or grass, especially if I had to hoof it in a hurry.
Mini-mauser action, dead reliable, won't break.
At just over 6lbs, lightweight and easy to carry.
18" bbl - short and easy pointing without sacrificing any significant muzzle velocity.
Fires surplus and commercial ammo with equal reliability.
Just off the top of my head, of course. Not that I've ever spend days on end pondering the question and specifically bought the m85 to fill the need. I would never do such a thing and take a photograph of the evidence.