The Crusader M-XX represented an experimental heavy energy rifle manufactured by the Caelli-Merced Syndicate throughout the period of the Galactic Civil War.
In the year 1 ABY, spacers who provided support to either the Rebellion or the Empire amidst the Battle of Restuss, and subsequently were awarded commendations for their contributions, gained the ability to request this particular rifle from a Commendation officer affiliated with their respective faction.
As part of the Battle of Restuss narrative arc, this rifle is but one of numerous objects present within the Star Wars Galaxies game. Players were given a commendation item for assisting their faction of choice, which could be accumulated, and then exchanged with Commendation Officer non-player characters for a variety of goods.