https://www.gamespot.com/articles/fortnite-adding-heavy-shotgun-very-soon-update-out/1100-6457592/

Update: Fortnite's new Heavy Shotgun is available now. The latest weapon to join the game's Battle Royale mode has been added to PS4, Xbox One, and PC, though there's no sign yet of the Flame Grill Floor Trap in Save the World. We'll update if we spot it. Original story follows.

A new update is coming to Fortnite tomorrow, March 22, potentially shaking up the competitive scene with two weapon additions. The 3.3.1 update will add the Heavy Shotgun to Battle Royale mode, and the Flame Grill Floor Trap to the Save the World mode. Exact timing for the update is said to be coming soon.