Not a definitive answer, but will help with proper gassing of the AR-15, whether you are over gassed, under gassed (short stroking) and what the proper ejection should be: The most common thing I see on the forums is short stroking. There can be many issues, one is to make sure you have your gas block installed correctly. It does not push against the shelf behind it on the barrel, there should be a small gap for proper alignment. Most barrels have dimples where the set screw should seat for proper gas block alignment. Other issues of no ejection, gas tube is upside-down. First thing on any new build or new gun is to clean the chamber and bore thoroughly, especially on Melonite treated barrels. I also like to give a quick polish to the chamber with a felt dremel wheel and Flitz, along with the feed ramps.