failure to extract or eject

First thing I would do, is take it apart and really check over the bolt. look for dirt, grime, carbon build up, etc. test the spring pressures of the extractor and the ejector (the spring clip thingy on the side of the bolt, and the round rod that sticks out of the bolt towards the chamber) make sure the spring tensions on both of them are good, that nothing is bent or binding.

lube it all up and try again.

not sure I can picture what you're saying...the bolt is hitting the shell before it's fully ejected out the port? does it get jammed into the 'port window' as the bolt comes forward?

take a picture of the jam and show us. does it look the same every time?

it sounds like maybe the bolt carrier group isn't getting blown back far enough., which could mean the gas tube is dirt/plugged, or that the whole upper receiver is dirty/needs lubed up.


Beyond that, I am not of much help. all of the civilian or military AR rifles that I've shot, I've never had a problem that wasn't fixed by breaking it down and cleaning everything very well, and lubricating all the moving parts, or replacing a junk magazine (since you're getting this malfunction when shooting just one round at a time, it's not likely that it's the mag, but to be sure, try shooting it one round at a time, with no mag inserted)