CFE223 and BL-C(2) are never going to work for a 300 blackout, way too slow. To have one powder for all three of those cartridges it would have to be of the fast, rifle variety. CFE blackout may also work in 223, but I don't see any loads listed where I usually look. Your best bet is to try something the others have mentioned such as AA1680, IMR/H 4198. More than likely you are going to need (at least) two different powders on hand to find an accurate load for all three.