ninepointer-Not to hijack the thread, but the way frame cracking was explained to me was that all sxs gun barrels have a forceful downward bend upon firing. Some call this "flip" and you can see it in point of impact problems with loads in some guns. The longer and lighter the barrels, the bigger the bend. The long barrels are a lever working against the angle of the frame. The frame will crack at the angle and frequently flow towards the hammer axles and then to the sear axles. The heavier the shot charge, and the faster the load, the more pronounced this becomes. Just keep everything moderate and you'll probably be fine. I know a guy with a 20 flues and he uses it with no problems.