I have a nova 20 gauge that is not functioning like it should. Using standard Federal 2-3/4 7.5 shot target loads. I press the forend release to open the chamber and load the first round then push the forend forward to close the chamber. I then load two more shells in the magazine tube. After firing the first shot, the forend will not move back to eject the spent shell and then chamber the second round. It will open if I again press the release and pull back to eject the spent shell. I have cleaned this gun regularly and do not see what is causing this malfunction. Anyone else experience this or have an idea why?