<p>The muzzle brake with compensator is a device mounted on the barrel muzzle to reduce recoil force during gun barrel discharge, experiencing a complex thermo-mechanical condition during its working cycle. Numerical simulation of the brake’s working environment was conducted in a 3D numerical domain using ANSYS Fluent. Temperature and stress fields were obtained through fluid-structure interaction using ANSYS Fluent, Transient Thermal, and Transient Structural. An experiment was carried out to determine the temperature and stress dependency of the brake over time, utilizing thermocouples and strain gauges on the outer surfaces, as well as a thermal camera to monitor temperature changes on the inner surfaces. Comprehensive comparisons between numerical and experimental results were made, showing good agreement. A comparative analysis of the brake’s working cycle, with and without projectile movement, revealed that the presence of a projectile significantly affects the temperature distribution and the maximum brake and compensator forces during the movement period, while its influence on forces impulses and brake efficiency is much smaller. This type of numerical analysis enables better optimization of brake design parameters and material selection for improved resistance and erosion prevention.</p>