Guns command minecraft (version 1.14.4)?

I'm currently building a map where you should have guns eg. A pistol, I wanted to have a pistol, an Ak 47 and a shotgun, my plan was to hack Minecraft to give this command that the snowballs do the damage, just shoot over a texture pack to give it a different texture.

But does anyone know how I do that the hoes in a different cycle snowballs or so shoot the damage?

How about if you just use a mod and mention when uploading your map that the mod is needed

Yes would also work but I basically wanted to stay on vanilla