The crossword solution for the term 'small rounded mass' is WAD, which is an acronym for a type of ammunition. A WAD is a small, round piece of material, usually made of paper, plastic, or felt, that is used to seal propellant powder in a shotgun shell or cartridge. It also helps to keep the shot or bullet in place and provides a gas seal so that the propellant's gases are directed behind the projectile.