Electromagnetic-driven projectile spin launching technology is an important way to achieve high-precision firing in the railgun, but there is still a lack of sufficient research on the structural design of the tail-connected revolving armature and experimental verification of the spin launching performance. In this article, first, a structural design scheme of a revolving armature with a tail-end connection is established and compared with the conventional armature structural design scheme. Second, the finite element calculation model of interference assembly is adopted, and the influence law of the improved armature structure parameters on the initial mechanical performance is obtained. The theoretical calculation results show that the change of armature structural parameters has a great influence on the contact area and little influence on the maximum equivalent stress. The contact force decreases sharply with the increase of the interference position L2, throat radius r , and crack width c_w of the tail, and increases sharply with the increase of the tail thickness t and interference amount A. Finally, the electromagnetic launching experiments with different launching energies are carried out on test projectiles with conventional armature and tail-connected armature. The experimental results show that the revolving armature with a tail-end connection can effectively improve the rotation speed, but it will also have some negative effects on the muzzle velocity and the contact state between the armature and the rail in the bore.