I bought a complete upper, but I have a new development.
I think I need to cut ramps in the upper receiver to get it to feed properly.
Please refer to the pic in my previous post that has a picture of the receiver. Can you see where the brass is hitting? If there were a feed ramp extended into the upper receiver would it be fixed?
Here is a pic of what it does to my bullets. The bullet is situated so that the right side in the pic is where the bottom of the bullet would be in the chamber. Observe what it does. It bends my bullets! Probably due to the drag on the lower. That's why I'm having feeding problems is because the BCG is petering out and using all of the energy on charging the round.