That's soooooo Hollywood!
Could be done. You would have to cross the gas tubes between them, and connect the trigger to the hammer on both barrels, but only charge one.
Then when you fired the first one, it would cycle the second one, so the spent round would remain in #1 with the hammer down and #2 would be loaded and hammer set back. So trigger would then fire #2, leave it hammer-down, and cycle #1.
The hard part would be determining a way to avoid chambering both barrels at the same time...doing so could be considered "more than one round with a single trigger operation" and BATFE wouldn't like it. Maybe some kind of interlock that prevents both hammers from setting back at the same time.
Needs two sets of sights. Maybe the red dot is for one barrel, and the irons the other one?
Needs two sets of sights. Maybe the red dot is for one barrel, and the irons the other one?
an over-under design instead of sxs might fix this problem.