This study attempted to examine the ballistic resistance of sandwich structures with aluminum facesheets, polyurethane core and polyurethane foam reinforced with aluminum pins. The main focus was on the effect of variations in density of core foam and the effect of adding different percentages of aluminum pins on energy absorption and ballistic resistance of sandwich structures under the impact of blunt and conical nose projectiles at high velocities (170 to 260 m/s). The results firstly demonstrated that any increase in the density of foam led to greater energy absorption. Secondly, the ballistic limit of sandwich structures with composite core was more than the foam core by 18 percent. Thirdly, the use of aluminum pins not only enhanced core resistance, but also altered the shape of damage and energy absorption in the rear facesheet. Finally, the ballistic limit of blunt projectile was greater than that of conical nose projectile.