The Ogryn Ripper Gun was designed by the Imperium as a standard issue weapon for the plethora of Ogryns that the Imperial Armies have hanging around during times of war. They are short ranged and heavily built to compensate for ogryns heavy handedness and make a serviceable club if it should run out of ammo, they are the perfect assault weapon for the ogryn. Ripper guns are fitted with locks to stop the ogryn from firing all the rounds off in one burst.
Ripper guns are so heavy and cumbersome that only ogryns can use them effectively. In-fact heavies would rather tool up with a better heavy weapon like a heavy bolter than encumber themselves with a ripper gun.