unless you have the strange RF barrel that comes with the combo rifles, the RF and CF chambers are in the center of the barrel. The frames have the fireing pin offset on the RF frames. Barrels will fit either frame, if you put a RF barrel on a CF frame the pin will strike the center of the RF cartridge, a CF barrel on the RF frame the pin will strike the edge of the primer. If you have an adaptor to use a .22mag in a .223 then it will work on a .223 with the CF barrel and CF frame. Larry