I'm selling some guns for the family of a recently-deceased friend. I test-fire everything before putting it up for sale, just so I know it is functional. Anyway, one of the pieces is a KBI (made in Russia by Baikal, I believe) O/U 12 ga., single trigger. I'm not real familiar with O/Us, but knew that some have barrel selectors. Saw no selector and figured it must just go to the second barrel after the first has discharged. Well, both went off at the same time. I do know THAT'S not supposed to happen. Anyone know anything about these things, i.e. is this something I, with my minimal 'smithing skills, should be able to fix? Any help would be appreciated.