I just built my first 9mm ar15 using a complete QC10 upper with a 5.5" barrel and a QC10 lower, all glock.

I went to the range for the first time after lubricating everything lightly and kept getting jams where the previous round would fail to eject and get caught with the feed coming in and jam.

http://i1141.photobucket.com/albums/n596/mgolobic/Mobile%20Uploads/Fusion/4C83E890-64D2-4419-9DDC-E8FFB5CC245B_zpsm3cudils.jpg

I'm using a KAK shockwave with a 5.4oz buffer. I had to buy a lower parts kit from joe bob that was milspec as QC10 was sold out. I was shooting 115gr mag tech ammo.

Any ideas?

I bet they were stove piping too... Right? Try adjusting or bending the ejector so it sits closer to the bolt.

Try a regular carbine buffer to see if it improves.

Try some 124 or 147 grain ammo. Run a few hundred rounds of that and see how it operates.

Got the 1.50 in quarters in the buffer tube?  I had the same problem and even had one get behind the hammer from the bolt over traveling