Abstract: PCrMo steel is applied to many gun parts. Aiming at reducing wear of parts, wear analysis were conducted to study wear mechanism and law under the shooting and training conditions. Taking the cartridge stop shaft of cartridge stop device as the object, the hardness of both surface and section were measured by a microhardness instrument and micromechanisn were analyzed by scanning electron microscopy. The results show that the surface hardness of worn area was obviously higher than that of unworn area, and the hardness of sectioned surface layer was high. The worn area could be divided into first worn area, middle worn area and end worn area in viewing the surface morphology. The wear forms of first worn area, middle worn area and end worn area were severe surface flaking, severe cutting and mild wear. The wear mechanism was both impact-sliding wear and abrasive wear resulting in surface material loss and work hardening.