This paper presents the thermoelastic shock wave model components of projectile, target, and muzzle tube during the initial start of penetration. The penetration model is combined using pressure and temperature (e.g., mechanical and thermal shock) that act separately at the moment of penetration (a few microseconds) into a homogeneous or first-layer armor body. The armor’s shape and material will be investigated based on contact principal stress. The reciprocal influence between the penetrator and the armor in the aspect of the projectile nose shape will also be demonstrated. Moreover, the penetrator thermoelastic material’s durability will be examined, based on von Mises criterion. The examination for the initial elastic contact stress impact will be performed by using the explicit solution to temperature-displacement coupling equilibrium, based on commercial finite elements modeling. In addition, a modified impact contact stress model based on both mechanical and thermal energies was proposed and found to agree with the literature. Brief conceptual analysis of projectile–shield interactions was examined. Finally, shooting tube muzzle thermoelastic analysis was performed alongside a literature comparison, which was found to agree qualitatively and quantitatively. Muzzle tube material impact analysis was performed. Finally, it was concluded that muzzle tubes obey the rule that a shorter cylinder length tube develops higher muzzle tube principal stresses.