Research on certain type small caliber rifle for studying the effect of projectiles on the extrusion process. The extrusion test of H90 copper beaded and copper-clad steel was taken as an example to analyze the properties of projectile materials, and get the extrusion force change corresponding of different ammunition. Using the finite element simulation model, combined with the test results, the mathematical model of the extrusion process is derived and its correctness is verified. The verification results show that the numerical analysis results and the simulation results agree with the experimental data. Judging from the results of the analysis and calculation, the difference in the material of the bullet shell causes a large difference in the extrusion process.