Marking cartridge for conventional firearms that deposits marking media on impact with a target. The marking cartridge generally comprises a marking projectile containing a quantity of marking media beneath a frangible cap portion and having a more durable exterior surface adapted to engage the rifling of the barrel when fired. The marking projectile also may comprise a receptacle for marking media having a curled lip adapted to remove air during assembly and excess marking media to insure a consistent quantity of marking media is contained within the marking projectile. The receptacle defining a marking media cavity radially spaced from exterior bearing portion wall and having a mushroom shape. The marking cartridge also may comprise an extendable casing.