I have the same problem with my Nova 20ga. It is brand new and only has about 350 shells through it (2 3/4"). At first it worked fine but now it is dumping shells from the mag out the bottom when racking after the first shot. I sincerely hope it is just a simple issue that can be fixed with a good cleaning. However, I've cleaned it several times and it's still happening (about 30% of the time for me). I sent email to Benelli and I will take it back to the dealer to be checked as soon as I can get there.
I have been trying to find out more and here is what I could compile from the forums so far (maybe this will help others):
1. not loading the magazine correctly
2. not racking hard/quick enough
3. some build up is inhibiting the carrier from working properly
4. the carrier is bent or broken
5. the gun is broken
I know I'm loading the magazine properly and I've tried racking hard, soft, quick, slow, haflway, all the way, etc. So neither #1 or #2 is my problem.
I can actually see that the carrier does not go all the way to the down position when the forearm is pulled back. It goes to about midway of the next shell in the mag, stops there and then comes up as expected (although empty) when the forearm goes forward. The next shell in the mag then springs into the empty space BELOW the carrier and drops out of the gun So I believe my problem is #3, 4 or 5. Hopefully it is 3 and the dealer's gunsmith can clean it up and make it work!
I'm thinking of using my air compressor to blow it clean and maybe move some gun oil around in the mechanism.
Anybody have other thoughts on a fix for this?