I think the argument in itself about cartridge efficiency is flawed.
A cartridge is an assembly of components - hull, powder, cap and bullet.
Each component has specific properties. Gearing these components and balancing their properties first only in between themselves and then ultimatly with the driving assembly (chamber, barrel, ultimatly rifle and shooter) decides how well the cartridge performs it task.
One can well argue the efficiency of each component in a given system but comparing two systems means switching more than one component (variable) at once making analysis difficult.
