Mouse aim in orthographic view

How can I change the gun accuracy with mouse, the way the game is design is to rotate the player with mouse position, but the aim are a little off because there are some offset from player position and gun position. how can i make the ray and line renderer to aim/cast the ray where my mouse is.

 void Shoot ()
     {
         timer = 0f;
  
         gunAudio.Play ();
  
         gunLight.enabled = true;
  
         gunParticles.Stop ();
         gunParticles.Play ();
  
         gunLine.enabled = true;
         gunLine.SetPosition (0, transform.position);
  
         shootRay.origin = transform.position;
         shootRay.direction = transform.forward;
  
         if(Physics.Raycast (shootRay, out shootHit, range, shootableMask))
         {
             EnemyHealth enemyHealth = shootHit.collider.GetComponent <EnemyHealth> ();
             if(enemyHealth != null)
             {
                 enemyHealth.TakeDamage (damagePerShot, shootHit.point);
             }
             gunLine.SetPosition (1, shootHit.point);
         }
         else
         {
             gunLine.SetPosition (1, shootRay.origin + shootRay.direction * range);
         }
     }

 void Turning()
     {
         Ray camRay = Camera.main.ScreenPointToRay (Input.mousePosition);
  
         RaycastHit floorHit;
  
         if (Physics.Raycast (camRay, out floorHit, camRayLength, floorMask))
         {
             Vector3 playerToMouse = floorHit.point - transform.position;
             playerToMouse.y = 0f;
  
             Quaternion newRotation = Quaternion.LookRotation(playerToMouse);
             playerRigidbody.MoveRotation(newRotation);
         }
     }