Owner of a Stevens 411. Have shot about 200 rounds through it. About 150 rounds in, both barrels went at same time. Then, on my SD pheasant trip, had it happen 2 times in about 35 rounds. 1st time happened shooting clays from a gun down position and other 2 times were on shots I pulled up and fired very quickly. Have any of you had this happen? Have tried to repoduce it empty to no avail. However, have been able make each barrel go off seperately and almost simultaneously. So do you think I or the gun are to blame.