What about your grip?
You mentioned that you are new to semi-autos, right?
What grip are you using? My reason for asking is that Glocks, being lighter than their all steel counterparts, really do
require a correct grip to function. If you are not using a practiced two-handed grip, here are some fundamentals:
1) unload the pistol and make it safe
2) grip the pistol in your shooting hand, with your hand positioned as high on the frame as you can, gripping the frame with three fingers. This grip creates a gap between the meat of your thumb and the three fingers.
3) with your support hand, put the meat of your thumb into the gap created by your shooting hand, rotating your support hand forward slightly.
4) wrap the fingers of your support hand around the knuckles of your shooting hand, but do not let your support hand index finger touch the front of the trigger guard, keep it low, over your other knuckles
5) position your thumbs so that they both point forward, but so that they do not exert any pressure on the frame, and so that you avoid touching the Slide Stop Lever when shooting
6) pull the trigger straight back using the middle of the pad of the tip of your trigger finger.
Sorry if this sounds basic, but grip problems are very common with new Glock shooters, and they are a common cause of function problems. If your grip is correct, the gun should work fine. If you have cheap ammo that really dirties up the gun, clean the gun and use a correct grip before making any judgments about the gun. If you aren't making progress, have an experienced Glock shooter try the gun.
Chris