Abstract: Two kinds of structural projectiles of different materials were designed in this paper, and an experimental study of 11kg projectiles penetrating the reinforced concrete target at 1400m/s was carried out by a 203mm Davis gun. Based on the experimental results, the structural response, penetration ability and related engineering issues of the projectile are discussed. The results show that when the reinforced concrete target is penetrated at a velocity of 1400 m/s, the heads of projectiles made from two different materials experienced erosion and developed a mushrooming effect. This was caused by high temperatures resulting from friction between the projectile and the concrete during penetration, which significantly softened the projectile's surface. Furthermore, the contact pressure between the two exceeded the yield strength of the projectile's surface, causing the shell material to enter a state of plastic flow, ultimately leading to the erosion and mushrooming of the projectile head. Additionally, the surface material of the shell was stripped from the projectile due to the cutting action of the hard aggregates in the concrete, resulting in severe abrasion of the projectile body. When comparing the structural responses of projectiles made from different materials, it was evident that material properties influenced their behavior. Compared to 30CrMnSiNi2MoVE, DT1900—known for its higher strength, hardness, and better resistance to impact compression—showed less erosion at the projectile head. However, its inferior shear resistance and wear resistance led to more severe abrasion on the projectile body. The mass loss patterns under high-speed penetration for conical structure projectiles differed from those of solid long-rod projectiles, with mass loss primarily concentrated in the projectile body. The conical flared tail design, while suppressing ballistic deflection, increased the contact area between the projectile body and the target, enhancing the abrasive and cutting actions of aggregates and steel. Moreover, under high-speed penetration conditions, the erosion and mushrooming of the projectile head could reduce the penetration depth to some extent; the less erosion at the head, the greater the penetration depth. In experiments, the maximum penetration depth of DT1900 projectiles could reach up to nine times the length of the projectile.