there are adapters to allow you to shoot a smaller ammo in a shotgun. Do these work well? what are they called and were are they available?I have a greener in 10 ga and ammo is just not there if you find 10 it is 3in mag not going to work in a gun this old.I was thinking of taking it down to 12 or 16 ga. if the adapters would work and the pattern would still be acceptible. advice apreciated.