A rotor blade for a gas turbine configured for use within a row of samely configured rotor blades. The rotor blade may further include: an airfoil defined between pressure and suction faces; and a midspan shroud comprising a pressure wing and a suction wing extending from the airfoil. The pressure wing and the suction wing of the midspan shroud may be configured so to cooperatively form an interface between installed neighboring ones of the rotor blades within the row of samely configured rotor blades. One of the pressure wing and the suction wing may be designated a first wing, and the first wing may include a chamber hollowed through a first surface of the first wing. The first surface of the first wing may include one of: a circumferential face formed at a distal end of the first wing; and a contact face of the first wing.