Of course the damage is greatly reduced. There is much less kinetic engery in the round. While the damage might be the same at 30,50,100 m, or the effective damage even better, it'll be greatly reduced after that distance.
The effective (lethal) range for a 7.62 subsonic, shot by a silenced sniper rifle is set with 170m.
The smaller the round, the less kinetic energy it stores at low speeds, the less effective range it has.