Particle settings for instant / fast laser?

particle system have a property called start speed for the initial velocity, you can change also the color over life time for reduce the alpha. and for shoot from the crosshair depends on how you coded the particle emision, but you can instantiate it in a empty transform inside the crosshair.

Awesome!! Would you be able to check my code for the particle system? I added it to the muzzle of the gun thinking that would be the best way at the time

 using UnityEngine;
 
 public class Gun : MonoBehaviour
 {
 
     public float damage = 10f;                  //Damage
     public float range = 500f;                  //Range of bullet
     public float fireRate = .50f;               //Greater fire rate = less time between shots.
     public float impactForce = 30f;             //Impact (velocity)
     public ParticleSystem Rail;
     public Camera fpsCam;                       //Camera. Click and drag off of hierarchy
     public GameObject impactEffect;             //Prefab system for impact
    
     private float nextTimeToFire = 0f;          //Instant shot (no lag when pressing down)
 
     void Update()
     {
 
         if (Input.GetButtonDown("Fire1") && Time.time >= nextTimeToFire)
         {
             nextTimeToFire = Time.time + 1f / fireRate;
             Shoot();
 
         }
 
     }
 
     void Shoot()
     {
 
         Rail.Play();                      //Play muzzle / barrel
 
         RaycastHit hit;
         if (Physics.Raycast(fpsCam.transform.position, fpsCam.transform.forward, out hit, range))
 
         {
             
             Target target = hit.transform.GetComponent<Target>();
             if (target != null)
             {
                 target.TakeDamage(damage);
             }
 
             if (hit.rigidbody != null)             //Hit rigidbody component
             {
                 hit.rigidbody.AddForce(-hit.normal * impactForce);
             }
 
             GameObject impactGO = Instantiate(impactEffect, hit.point, Quaternion.LookRotation(hit.normal));
             Destroy(impactGO, .25f);  // Destroy impact effect 
             {
                
             }
 
         }
     }
 }