The pulse gun was a massive cannon which was attached to the unique weapons platform of the Special Weapons Dalek in lieu of the basic gunstick and manipulator arm. (PROSE: Remembrance of the Daleks) It was characterised by the Dalek Combat Training Manual as a "long-range, high-intensity laser cannon". (PROSE: Dalek Combat Training Manual)
More powerful than the standard Dalek gunstick, a single shot from the pulse gun could utterly destroy a pair of Renegade Daleks. (TV: Remembrance of the Daleks)
During the Last Great Time War, Temporal Weapon Daleks made use of Temporal Cannons which appeared cosmetically similar to the pulse guns. These cannons, however, were capable of erasing their targets from history. (PROSE: Engines of War)