What pistol do you have? Definately try a few different brands of ammo. Firm wrist and elbow. Let someone else try it, to see if it does same thing. If still having problems call them.
Firing pin? Is the firing pin part of the extraction/ejection process?When it does feed, how far do the empty eject? if it doesn't eject far and the incoming round is hitting the outgoing one its a bad firing pin assembly