The problems are not from too tight of a constriction, they are from the ported "wad stripping" chokes. The aftermarket chokes that are extended and ported are designed to strip the wad away from the load and provide a tight pattern. Federal designed its "Flite Control" to strip away from the shot on its own. If you shoot them from a non ported choke, you will like them and they will likely pattern well for you. You probably won't get very good results from a ported choke though. Federal Heavy Weight shot is the heaviest available commercially too which is a good thing. It s15 gm/cc where lead is 10-10.5 and Hevi shot is 12. Very dense heavy stuff.
Lee
This is exactly as I have found with the Fed Flite Control loads. I've shot #5 & 6's in my chokes with ports, they do not pattern well. I have pards that shoot them in non-ported chokes and like them. I've seen them roll birds over easily at 45yds
I shoot Win Supreme #5, and they work for me.
