The Disruption Rifle, otherwise known as the Concussion Rifle, is a Protoss heavy infantry weapon.
The Disruption Rifle fires explosive bolts of antimatter plasma sheathed in psychically charged fields. A similar weapon is used by the Dragoon and Photon Cannon.
When the plasma bolt hits a surface, it produces area-of-effect damage and a small "kick" to effected objects within the blast radius. The plasma projectiles also have a slight downward arc to its shots.