An indirect fire mission training round includes a projectile training shell having an outer periphery, a proximal end, and a distal end, the proximal end defining an interior chamber. The projectile training shell is configured to be inserted within a cavity of a projectile firing instrument. The round includes an interlock member configured to securely receive a proximal portion of a subsequent training round within the interior chamber of the projectile training shell. The round includes a resistance brake extending outward from the outer periphery and configured to contact a wall of the cavity of the firing instrument and provide resistance that secures the projectile training shell at a position within the cavity. The resistance break is selectively disengageable such that the position of the projectile training shell is adjustable.