Machine Gun shooting

Hello! I have the TankShooting Script from the Tanks! Tutorial and I need help converting it into a script where when you hold the fire button, it doesn't recharge but constantly shoots, like a machine gun. I'm using the TankShooting script on all my guns, but they only fire one shot at a time.

Here is the script:

 using UnityEngine;
 using UnityEngine.UI;
 using UnityEngine;
 using UnityEngine.UI;
 
 public class TankShooting1 : MonoBehaviour
 {
     public int m_PlayerNumber = 1;              // Used to identify the different players.
     public Rigidbody m_Shell;                   // Prefab of the shell.
     public Transform m_FireTransform;           // A child of the tank where the shells are spawned.
     public Slider m_AimSlider;                  // A child of the tank that displays the current launch force.
     public AudioSource m_ShootingAudio;         // Reference to the audio source used to play the shooting audio. NB: different to the movement audio source.
     public AudioClip m_ChargingClip;            // Audio that plays when each shot is charging up.
     public AudioClip m_FireClip;                // Audio that plays when each shot is fired.
     public float m_MinLaunchForce = 15f;        // The force given to the shell if the fire button is not held.
     public float m_MaxLaunchForce = 30f;        // The force given to the shell if the fire button is held for the max charge time.
     public float m_MaxChargeTime = 0.75f;       // How long the shell can charge for before it is fired at max force.
 
 
 
 
     private string m_FireButton;                // The input axis that is used for launching shells.
     private float m_CurrentLaunchForce;         // The force that will be given to the shell when the fire button is released.
     private float m_ChargeSpeed;                // How fast the launch force increases, based on the max charge time.
     private bool m_Fired;                       // Whether or not the shell has been launched with this button press.
 
 
     private void Start ()
     {
         // The fire axis is based on the player number.
         m_FireButton = "Fire" + m_PlayerNumber;
 
         // The rate that the launch force charges up is the range of possible forces by the max charge time.
         m_ChargeSpeed = (m_MaxLaunchForce - m_MinLaunchForce) / m_MaxChargeTime;
     }
 
 
     private void Update ()
     {
         // The slider should have a default value of the minimum launch force.
         m_AimSlider.value = m_MinLaunchForce;
 
         // If the max force has been exceeded and the shell hasn't yet been launched...
         if (m_CurrentLaunchForce >= m_MaxLaunchForce && !m_Fired)
         {
             // ... use the max force and launch the shell.
             m_CurrentLaunchForce = m_MaxLaunchForce;
             Fire ();
         }
         // Otherwise, if the fire button has just started being pressed...
         else if (Input.GetButtonDown (m_FireButton))
         {
             // ... reset the fired flag and reset the launch force.
             m_Fired = false;
             m_CurrentLaunchForce = m_MinLaunchForce;
 
             // Change the clip to the charging clip and start it playing.
             m_ShootingAudio.clip = m_ChargingClip;
             m_ShootingAudio.Play ();
         }
         // Otherwise, if the fire button is being held and the shell hasn't been launched yet...
         else if (Input.GetButton (m_FireButton) && !m_Fired)
         {
             // Increment the launch force and update the slider.
             m_CurrentLaunchForce += m_ChargeSpeed * Time.deltaTime;
 
             m_AimSlider.value = m_CurrentLaunchForce;
         }
         // Otherwise, if the fire button is released and the shell hasn't been launched yet...
         else if (Input.GetButtonUp (m_FireButton) && !m_Fired)
         {
             // ... launch the shell.
             Fire ();
         }
     }
 
 
     private void Fire ()
     {
         // Set the fired flag so only Fire is only called once.
         m_Fired = true;
 
         // Create an instance of the shell and store a reference to it's rigidbody.
         Rigidbody shellInstance =
             Instantiate (m_Shell, m_FireTransform.position, m_FireTransform.rotation) as Rigidbody;
 
         // Set the shell's velocity to the launch force in the fire position's forward direction.
         shellInstance.velocity = m_CurrentLaunchForce * m_FireTransform.forward;
         ;
 
         // Change the clip to the firing clip and play it.
         m_ShootingAudio.clip = m_FireClip;
         m_ShootingAudio.Play ();
 
         // Reset the launch force.  This is a precaution in case of missing button events.
         m_CurrentLaunchForce = m_MinLaunchForce;
 
     }
 }

Any help is appreciated!