Prevent minigun from freezing Garbage Collector if it's spawned by itself; (#19666)

Also actually prevents minigun from firing if it's overheater;

code/modules/projectiles/guns/projectile/laser_gatling.dm

@@ -124,11 +124,11 @@
 	else
 		qdel(src)
 
-/obj/item/weapon/gun/projectile/minigun/shoot_live_shot(mob/living/user as mob|obj, pointblank = 0, mob/pbtarget = null, message = 1)
+/obj/item/weapon/gun/projectile/minigun/process_fire(atom/target as mob|obj|turf, mob/living/user as mob|obj, message = 1, params, zone_override)
 	if(ammo_pack)
 		if(ammo_pack.overheat < ammo_pack.overheat_max)
-			. = ..()
-			ammo_pack.overheat++
+			ammo_pack.overheat += burst_size
+			..()
 		else
 			user << "The gun's heat sensor locked the trigger to prevent lens damage."
 
@@ -141,9 +141,9 @@
 	if(!ammo_pack)
 		if(istype(loc,/obj/item/weapon/minigunpack)) //We should spawn inside a ammo pack so let's use that one.
 			ammo_pack = loc
+			..()
 		else
 			qdel(src)//No pack, no gun
-	..()
 
 /obj/item/weapon/gun/projectile/minigun/dropped(mob/living/user)
 	ammo_pack.attach_gun(user)