This study presents a finite-volume-based numerical simulation of a 120 mm mortar shell to estimate the aerodynamic forces acting on it at different Mach numbers. Simulations are conducted over a Mach number range of 0.6–0.9 to evaluate the aerodynamic loads and the associated temperature variations. Mortars are typically subsonic projectiles that follow a parabolic trajectory. Despite their subsonic nature, the high initial velocity necessitates thermal and aerodynamic considerations for effective projectile design. A density-based solver is employed to solve the compressible Navier–Stokes equations. Additionally, the study is extended to assess the static and dynamic stability of the shell. Static stability analysis is performed using Barrowman’s equations, while the dynamic stability factor is numerically calculated across different Mach numbers to evaluate the dynamic stability of the 120 mm mortar shell.