In this paper, an analytical study of high-impulse current measuring shunts with cage configuration is presented. Through the use of the partial mutual inductance method, an equivalent first-order model is developed, and a discussion of the minimization of the time constant taking into account physical constraints for two different materials is presented. The transfer function of the measuring circuit is provided, and the possibility of compensating the inductance via the use of rectangular loops formed by the sensing wires and placed inside the cage is shown. The derived model is tested on a homemade shunt prototype with application to an electromagnetic rail launcher. The experimental results confirm the validity of the model and its robustness with respect to the geometrical parameter uncertainty.