I noticed you said that the shells were striking your nose occasionally. Is it possible that you aren't gripping the firearm firmly enough?
Have some stalwart fellow (with riot helmet or motorcycle helmet with face shield lowered) try your firearm. Stand about six feet behind your soon-to-be former friend and observe the trajectory of the ejected cases while (s)he empties the magazine. A good working gun in the hands of a proficient shooter should eject the cases along the same trajectory all the time. If your gun does this, it isn't the gun. Just a thought.
[This message has been edited by 4V50 Gary (edited 11-02-98).]