[Admins]

shootarrow() takes the position of the npc/weapon that shoots the arrow. Weapons are automatically moved to the player position. You cannot change the weapon position if you are on a gmap.
About triggering another weapon: If you call the function of the other weapon directly it is not syncing the position, only if the weapon receives an event (onWeaponFired, trigger etc.). I suggest using a simple approach and calling shootarrow in the original weapon script (or pass the weapon object to the other function and then call callerweapon.shootarrow()).