Not being totally inimate with novas, I can only guess without seeing the gun in person. The problem sounds like the slide "action bar". You NEED to return it for repair, assuming it's still under warranty, or take it to your nearest gunsmith. That's a new 1 on me, and should be pretty rare problem as I've never had 1 come in for repair due to that particular problem (truth be told-rare to get them in for repair any reason).