devtrackers.gg
I'm using fire grenades, fire chem launcher, and fire turret. I make kills all the time with fire and other status effects. I've gotten like 6 crossbow bolts to drop in 2 days. Something is bugged.
As a reminder, the special ammo has a chance to drop from certain types of kills depending on the Specialization. It is not guaranteed even when performing that type of kill.
That said, I can understand the frustration over the randomness of getting said ammunition... particularly for Survivalist.