By way of example, they are the knife and the spear.

unfortunately, a projectile cannot be used. Due to not having a weapon equipped, the event getdata does not correctly retrieve the weapon, so it fails to apply the damage.

It could be applied as a projectile, but hit zones should be ignored. (I would ignore the armor of a shield for example).

Could it be implemented?
Yes, you could lock the item on the QuickBar until the projectile makes contact.
But since the projectile can take time to hit, we prefer to implement it as a line trace. .