Writing this post for some advice. My brand new 20SF had a problem right out of the box. 2 misfires in the first 50 rounds (First was on round 6). Then a couple of weeks later, after 100 or so more rounds, another misfire with a different type of ammo. I did send the pistol back to Glock, to straighten it out, and waiting for its return. My experience with most repairs on products with intermittent malfunctions is that I will again see the problem sometime in the future, as intermittent malfunctions are not easily diagnosed and repaired, so I will be stuck with it. Is there anything I can do to increase the reliability of this weapon? Any modifications? Or should I just trade it in if the problem persists?