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This paper describes the process of creating a numerical FEM (finite element method) model of the 5.56 × 45 mm SS109 projectile. The model was used to calculate the temperatures occurring in the projectile materials during the impact on the steel plate at an angle of 45°. The purpose of the investigation is to estimate the ability of a ricocheting projectile to cause ignition. For the same projectile, experimental tests were also carried out under the conditions adopted for the numerical investigation in order to validate the FEM model. During the experiment, temperature was measured with a thermal camera; the phenomenon was also recorded with a colour high-speed camera.

The article presents the results of tests on the temperature of propellant gases shortly after the bullet leaves the barrel. The temperature and movement of these gases were recorded with thermal cameras and a high-speed camera. Weapons with and without muzzle devices (flash suppressor, silencer) were used. The aim of the research was to check the capability to ignite flammable gases located in the vicinity of the propellant gases produced during firing. Comparison of the maximum temperature of the propellant gases and the ignition temperature of the flammable gases makes it possible to determine the probability of fire. The lowest temperature of propellant gases was in the case of shooting with 9 × 19 mm bullets with the lowest kinetic energy (518 J), and the highest temperature of these gases was during shooting with 5.56 × 45 mm HC (SS109) bullets with the highest kinetic energy (1,785 J).

The article presents results of research and analysis of the currently conducted project aiming at the development of a flexible impact protector. The need to carry out the work results from the necessity of the ever-wider and more frequent use of body armours, including those resistant to blunt impacts, by the army, police and other public security services as well as a demand for impact protective elements in the civilian market. In the first part, the assumptions regarding the protective coverage under development and the origin of the topic with reference to earlier work on the use of non-Newtonian fluids in body armours are indicated. Next, the requirements for impact protectors and a review of the state of the art in the scope of this type of protective elements are presented. Finally, the results of the impact tests of armour samples are shown.