I can't make my player to shoot faster (Check script for reference)

Hello everyone! I was making a player shooting script and was having some trouble. The normal shooting works just fine, but there’s a problem with the part where I increase the rate of fire. There is a collider (which is a trigger) in the script, which activates the shooting frenzy for 10 seconds. But when I touch the collider nothing happens. Does anyone know what’s wrong here? Thanks.
using UnityEngine;

    public class PlayerShooting : MonoBehaviour
    {
        
    	public int damagePerShot = 20;
        public float timeBetweenBullets = 0.15f;
        public float range = 100f;
    	public float delay = 1f;
    	float nextUsage;
        float timer;
    	int time = 0;
        Ray shootRay;
        RaycastHit shootHit;
        int shootableMask;
        ParticleSystem gunParticles;
        LineRenderer gunLine;
        AudioSource gunAudio;
        Light gunLight;
        float effectsDisplayTime = 0.2f;
    
    
        void Awake ()
        {
            shootableMask = LayerMask.GetMask ("Shootable");
            gunParticles = GetComponent<ParticleSystem> ();
            gunLine = GetComponent <LineRenderer> ();
            gunAudio = GetComponent<AudioSource> ();
            gunLight = GetComponent<Light> ();
    		nextUsage = Time.time + delay;
        }
    
    
        void Update ()
        {
            timer += Time.deltaTime;
    
    		if(Input.GetButton ("Fire1") && timer >= timeBetweenBullets && Time.timeScale != 0)
            {
                Shoot ();
            }
    
            if(timer >= timeBetweenBullets * effectsDisplayTime)
            {
                DisableEffects ();
            }
        }
    
    	void OnTriggerEnter(Collider c1)  //to increase rate of fire
    	{
    		if(time <= 10)
    		{
    			timeBetweenBullets = 0.05f;
    			if(Time.time > nextUsage)					//to make it execute once per second.
    			{
    				nextUsage = Time.time + delay;
    				time++;									//to count seconds
    			}
    		}
    		else
    		{
	                     timeBetweenBullets = 0.15f;
                             time = 0;
                 }

    	}
    
        public void DisableEffects ()
        {
            gunLine.enabled = false;
            gunLight.enabled = false;
        }
    
    
        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);
            }
        }
    }

I think your shootableMask ignore that ray to collider.Try with out shootableMask for your Physics.Raycast