The star grain configuration has proven to be very attractive for the efficient use of solid propellant rockets. Among the many advantages of star grain are the reduction of the inert mass of rocket motor structure; the protection of the chamber walls from excessive heating; and the possibility to attain relatively wide range of predetermined pressure. The effects of changes in various design parameters are studied in this paper, each design parameter is treated separately while the other parameters .are assumed constant. Different grain shapes are compared, for nearly the same mass of the propellant material. The investigated parameters include grain geometry, initial propellant temperature, erosion of the grain and erosion of the critical diameter. The results are compiled to demonstrate the variation of the head end pressure with time. The data used for these investigations are picked from real firing of artillery rocket.