This challenge is part of the Star Wars temporary Mission that followed the Fortnite event dedicated to the famous saga. You'll have to inflict a total of 200 damage points on opponents or Stormtroopers of the First Order with a Blaster Rifle.
The weapon with unlimited ammunition will easily be collected at the TIE Fighter crash site. You'll also find a squad of Stormtroopers to be massacred nearby.
Map
Be careful: even if Stormtroopers may not be very skilled, they are numerous in this area. Landing there directly can be risky. Except for a few small weapons here and there, the places are poor in loots as long as the clones are alive. The best solution may be to land somewhere else to equip yourself quickly and then attack the site.