For the 150 Hornady's and 175 Sierra's I'm waiting for CFE 223 to come out. Hodgeden has;

150 GR. HDY SP Hodgdon CFE 223 .323" 2.950" 54.0 2848 37,600 CUP 57.0 3054 46,900 CUP
175 GR. SIE SP Hodgdon CFE 223 .323" 3.100" 52.0 2615 36,500 CUP 55.0 2837 47,800 CUP

That is still under what the Remington can handle. I'm not going to hold my breath with their data, however.