In one example, a method includes running a downhole system into a downhole environment that comprises a wellbore, and the downhole system is configured such that a reusable plug of the downhole system is positioned uphole of a perforation gun of the downhole system, then, with the perforation gun, perforating a casing at a stage of the wellbore, and the perforating is performed using a projectile, and the perforating is performed by firing the projectile from a chamber of the perforation gun.