yeah gun weapons that instantly hit are called raycasting weapons. you can find them in most weapon packs like bushido's tier tactical, bushido's quake type weapons, gravity cat's guns (the black ones, not his firearm pack), and a few others.
some weapon packs are entirely made up of raycasts like h&k pre-alpha, gravity cat's weapons mentioned above, and blockombat. the guns are generally differentiated based on accuracy and range.