The TOZ is so sexy but eh, only two shots. A lot more practical in CoP at least, since then you can use it as a sidearm.
That was another thing about CoP that put it above the other two; the ability to equip whatever you wanted in whatever slot you wanted it.
The TOZ 88 is unavailable without mods. The sawn off version from the vanilla game is ok, but I'm talking about the one with the full length barrel. I used it mostly because the damage output outclassed most other shotguns, so reloading was never an issue. If it didn't die in one hit, you just had to empty the other barrel and sure enough what you shot WOULD go down. Anything short of a psudogiant that is. Chimera usually required both barrels center mass two, grazing hits weren't enough. It has the "saltmummy gutshooting seal of approval."
Special ammo, in that armory mod for clear sky, it adds these incendiary bullets with the description "These special bullets are made specially for entering the skull of a zombie and incinerating it's brain." Fun fact, they were also ideal for wrecking the living shit out of monolith soldiers.