Abstract: A cartridge includes a case, a primer, and propellant disposed in the case. The cartridge also includes a projectile at least partially received in the case. The projectile includes a main body that defines a counter-bore and a through-bore and a piston received in the main body. The piston includes a base, a head, and a shaft. The projectile defines a non-deployed state in which the base is entirely received within the counter-bore, a first portion of the shaft is received in the counter-bore and a second portion of the shaft is received in the through-bore, and the head is received in the through-bore. The projectile also defines a deployed state in which the base is received within the counter-bore and at least part of the head is not received in the through-bore.