I have a stevens .410 .22 over-under and the .410 works fine but the .22 keeps misfiring. I have used Aguila and Federal gold medal rounds. I got the Aguila cheap and i thought that it might be the ammo but its misfiring with the federal rounds too and i thought they were better quality. I fired thirty rounds with six misfires, and had to retry most of the others to get them to go off.It is fairly old and it was my dads so I want to try and get it to where it is in good working condition. The rims look like they were struck fairly hard, some were even bent a little but still didn't fire. Do you think that its just a bad batch of ammo or is something wrong with the gun. Thanks In advance for any advice.