I need some advice gents, I have a set of Charles Daly O&Us in 20 and 12 gauge.They were my Dad's and he would shoot trap with the boys often enough that they got in to the rules. I can't get these guns to dryfire(or live) both barrels one after the other. Is it possible that they have been modified to shoot only a selected barrel? They will fire a single barrel only and won't fire the other unless I select that barrel. Is there a simple flick of a switch or what?