One has to wonder if the "Peening" had some effect on this. Stop, think & consider. Wear in the hinge will not bring the lower portion of the bbls closer while showing a gap at the top. Assuming the bbls were properly fit to begin with & had a slight gap between flats & action bar, wear in the hinge allowing the bbls to seat down further & close the frame gap, would move the "Top" of the bbls more than the bottoms. A slight gap at the bottom while tight at the top, would appear normal. A bending of the frame would create a wider gap at the top. Quite possible this occured over the years of possible heavy loads & the peening brought the bbls back against the breech, but contact only at the bottom, due to the bent frame. I'd check it out good.
