RE: magnum vs 308 or 270 or 30-06
Use x bullet in a .308 and x bullet in a .300 mag and the .308 will out penetrate the .300mag because x bullet wasnt designed for 3000+ velocities and just explodes. So you put Y bullet into the .300 mag and it now expands and penetrates like x bullet in the .308, so your now right back to where we started.