In this work, we propose an alternative type of magnetic bolometer to be employed in the search of primordial B-modes in the CMB. These magnetic bolometers are an adaption of the well-known Metallic Magnetic Calorimeters used in particle physics. They rely on the magnetization dependence on temperature of alloys such as Au:Er and Ag:Er. In addition to the low intrinsic noise a magnetic bolometer of this nature offers, the broad and smooth magnetization dependence with temperature of metallic magnetic sensors ultimately translates to a high dynamic range and straightforward calibration.The results show how antenna-coupled Metallic Magnetic Bolometers are a promising detector architecture for polarization measurements of millimeter- and sub-millimeter-wave radiation. Their intrinsic noise equivalent power is estimated to be in the range of 10 to 100 aW / Hz1/2, which means background limited detection is possible.