entity newmis;
entity newmis2;   // to add a new entity

Step 2
Then, you'll need to go to the top of your weapons.qc file and find the W_PreCache function. Just add the lines inside the heading.

void() W_Precache =
{
        precache_sound ("weapons/r_exp3.wav");  // new rocket explosion
        precache_sound ("weapons/rocket1i.wav");        // spike gun
        precache_sound ("weapons/sgun1.wav");
        precache_sound ("weapons/guncock.wav"); // player shotgun
        precache_sound ("weapons/ric1.wav");    // ricochet (used in c code)
        precache_sound ("weapons/ric2.wav");    // ricochet (used in c code)
        precache_sound ("weapons/ric3.wav");    // ricochet (used in c code)
        precache_sound ("weapons/spike2.wav");  // super spikes
        precache_sound ("weapons/tink1.wav");   // spikes tink (used in c code)
        precache_sound ("weapons/grenade.wav"); // grenade launcher
        precache_sound ("weapons/bounce.wav");          // grenade bounce
        precache_sound ("weapons/shotgn2.wav"); // super shotgun 
      // Add the code in blue
        precache_sound ("enforcer/enfstop.wav"); // laser shot
      precache_sound ("enforcer/enfire.wav"); // laser sizzle
      precache_model ("progs/laser.mdl"); // laser model
        // End of additional code
};

Step 3
Third, open up your weapons.qc file and find the W_FireSuperShotgun function. Put the following code directly above it.

void() LaserHit =
{
        local vector org;
        
        if (other == self.owner)
                return;         // don't explode on owner

        if (pointcontents(self.origin) == CONTENT_SKY)
        {
                remove(self);  
                return;
        }
        //Sizzle noise that you hear when the enforcer's laser contacts
        sound (self, CHAN_WEAPON, "enforcer/enfstop.wav", 1, ATTN_STATIC);
        org = self.origin - 8*normalize(self.velocity);

        if (other.health)
        {
                SpawnBlood (org, self.velocity*0.2, 40);
                T_Damage (other, self, self.owner, 60); 
        // You can change the amount of damage it does
        }
        else 
        {
                WriteByte (MSG_BROADCAST, SVC_TEMPENTITY);
                WriteByte (MSG_BROADCAST, TE_GUNSHOT);
                WriteCoord (MSG_BROADCAST, org_x);
                WriteCoord (MSG_BROADCAST, org_y);
                WriteCoord (MSG_BROADCAST, org_z);
        }       
        remove(self);   
};

Step4
Now delete the W_FireSuperShotgun function and put this function in instead.

void(vector org) W_FireSuperShotgun =
{
    local vector dir; 
    local vector dir2;
    local entity newmis2;

    self.currentammo = self.ammo_shells = self.ammo_shells - 1;
    sound (self, CHAN_WEAPON, "enforcer/enfire.wav", 1, ATTN_NORM); 

    newmis = spawn ();
    newmis.owner = self;
    newmis.movetype = MOVETYPE_FLYMISSILE;
    newmis.solid = SOLID_BBOX;

    dir = aim (self, 1000);
    newmis.angles = vectoangles(dir);

    newmis.touch = LaserHit;
    newmis.classname = "laser";
    newmis.nextthink = time + 6; // Time before laser disappears
    newmis.think = SUB_Remove;
    newmis.effects = self.effects | EF_DIMLIGHT; // Make it glow a little
    setmodel (newmis, "progs/laser.mdl");
    setsize (newmis, '0 0 0', '0 0 0'); 

    setorigin (newmis, self.origin + v_forward*8 + v_right*-3 + '0 0 16'); // make it go a little to the left. 
    newmis.velocity = dir * 1000;
// What are you gonna see next is just a copy of whats above but with all the newmis renamed to newmis2 and all the dir renamed to dir2.
    newmis2 = spawn ();
    newmis2.owner = self;
    newmis2.movetype = MOVETYPE_FLYMISSILE;
    newmis2.solid = SOLID_BBOX;

    dir2 = aim (self, 1000);
    newmis2.angles = vectoangles(dir2);

    newmis2.touch = LaserHit;
    newmis2.classname = "laser";
    newmis2.nextthink = time + 6; 
    newmis2.think = SUB_Remove;
    newmis2.effects = self.effects | EF_DIMLIGHT; 
    setmodel (newmis2, "progs/laser.mdl");
    setsize (newmis2, '0 0 0', '0 0 0'); 
    setorigin (newmis2, self.origin + v_forward*8 + v_right*3  + '0 0 16');  //make it go a little to the right
    newmis2.velocity = dir * 1000;
};

Step 5
Well there you are, compile it and have fun with your SuperShotgun that now fires two laser bolts.. cool or what?, see ya.