In this paper, we consider the perforation of 5083-H131 aluminum armor plates by conical-nose tungsten projectiles. In all cases, we assume the perforation process is due to ductile hole growth. Therefore, we employ the cylindrical cavity-expansion (CCE) approximation to determine the ballistic limits and residual velocities of the projectiles in each of three different target plate thicknesses. For the CCE solutions we consider cylindrical cavities to expand from a zero initial radius at constant velocities in a homogeneous isotropic plane strain 5083-H131 aluminum armor plate. The plastic region is assumed to be an incompressible power-law strain hardening von Mises material surrounded by a compressible linear elastic region defined by the isotropic form of generalized Hooke's law. The model's predicted ballistic limits and residual velocities are obtained in terms of a proposed complete quadratic function representing the radial stress acting on a projectile's nose. Results are shown to be in good agreement with the experimental data for the three thicknesses of target plates considered with target inertia. When target inertia is neglected the results indicate that as the target thickness increases so do the target inertia effects and the solution does not correspond well with the experimental data. In addition, the proposed full quadratic function methodology can also be employed with other CCE models provided a reasonably good functional fit is obtained.