Slingshot not modded

I’m running 0.C with IceCoon’s weapons pack. I finally built a sling shot put pebbles in inventory and when I activated it I didn’t get the throw mode prompt to hit something just a message in the bottom right saying, “looks like your slingshot isn’t modded.” and then nothing same when I tried wielding it first. dont need to load a slingshot but I was sure I had pebbles so yeah. Please help. ThX in advance.

Press “f” to fire the slingshot, like a gun.