Actually, the QB stock and the Disco stock are VERY close to each other.... The trigger slot in the QB stock is about 1/4" longer and slightly narrower than the slot in the Disco stock but the hole for the stock mounting bolt is in the same place.... The groove in the top of the QB stock is a"whisker" narrower because the OD of the tube is about 0.010" smaller.... I just compared them, and to fit a Disco action in a QB stock you would have to sand out the channel for the main tube (and I mean sand, not router, you can almost force the Disco tube into place).... Then you would have to file the trigger slot a bit wider (maybe 1/16").... To fit a QB action in a Disco stock you may have to lengthen the back of the trigger slot slightly.... That's pretty much it....

OH!, you would have to cut a hole for the Disco pressure gauge in a QB stock.... that takes a 1" hole saw....

Bob