Anyone ever hear of a ring bulge in the choke area popping the ribs??
There was a KED-Grade Remington hammerless Double that my Father owned, and then passed on to his younger brother when he returned from WW-II. That gun survived decades of use with all manner of smokeless powder loads including plenty of Western Super-X and Federal Hi-Powers. In the early days of steel shot some of my cousins were shooting it goose hunting out in Western Minnesota, bulged the chokes and popped the ribs loose.
I've examined two of the quite rare Ithaca NID Magnum-Twelves with bulges at the start of the choke area, but neither had yet popped the ribs.