You will have to down load the 223 to keep from destroying the meat unless you will be making head shots only. Full velocity in the hornet might even be to much for close shots I'm not sure. Because of this I would choose the hornet.You will have to be careful with bullet selection also. I have not shot a turkey with a rifle as it is not legal here in GA, but I have seen what a full loaded 223 can do to smaller game. Maybe someone who has used rifles for turkey can give you more info as to which bullets and velocities work best.
BruceP