In military, empty cartridge recovery case of personal small arms is a device used to collect the empty cartridge after consumption of bullets. It has different shapes depending on the shape of small arms. However, It should be designed in a shape that wraps around the outlet for empty cartridge and it should be no restrictions to the movement of small arms. It has been used to spread military. but military is demanding design improvement due to frequent damage of empty cartridge recovery case. In this report, We improved the shape of the product in order to prevent damage to the product and verified through the FEM analysis and prototype test. According to the result of simulation, best modified modelling of this study has been reduced about 19% of the stress compared to initial modelling. In addition, modified products were confirmed durability, wearability and fixability through fire test.