A near-guaranteed method to achieve gold on this challenge is to unlock the unlimited ammo secret and use the aerial wastelander combo (+ +). This will destroy enough scoring targets to achieve the goal, and hitting the citizen targets will not deduct enough points to come up short. Wave Concussor gun course
Full Answer
The gun course from Jak II. The first gun course available utilizes the Scatter Gun, the advantage of which is its larger field of fire. However, this can also act as a disadvantage due to the demand of remaining within close range of your targets, which presents the hazard of shooting civilian targets.
While gun course training is initially used for game missions, they may be revisited afterward to earn nine Precursor orbs in total per course (with the exception of the Ratchet and Clank courses).
Dark Jak and Light Jak are not available. In order to rack up a high score in these gun courses, it is imperative to have liberal use of the Morph Gun and knowledge of the targets' patterns beforehand. Not to mention you can even press the select button on your controller to pause the game.
It is recommended to avoid spamming the trigger button, as the fury will deplete it very fast, despite the extra ammo crates placed around the course. Lastly, when firing full automatic, the Vulcan Fury has a tendency to aim at an angle slightly overhead of that of your enemies when at a certain distance.