I dunno, Im not good at trouble shooting guns...all i know is when you pull the trigger she dont go bang!
lol
I used it strickly for trap shooting my leagues. so it was only one round at a time. I went to shoot some trap with my brother, we were shooting double birds. loading two rounds at a time....first shot will always goes off normal, the quick pump and follow up shot on the next bird, and it will not shoot the second round. its like its not re-setting the hammer or something. I tried pumping it several different way thinking it was me, but no luck.
little bit later and it started doing it on the first round, and i can't have that happen when im on the line shooting for score so i gave up on the gun. I've owned 3-4 moss 500's and never had a problem with them....was told these were the same guns under a differnt name so i thought it would be fine.