https://www.gamespot.com/articles/new-fortnite-update-nerfs-smg-and-compact-smg/1100-6460751/

Epic Games recently added the SMG and Compact SMG to Fortnite: Battle Royale but, following feedback from its community, has pushed out a hotfix tweaking how effective they are. In a post on the Fortnite: Battle Royale subreddit, Epic said that SMGs were "stronger than we would like at the moment" and detailed the adjustments made to them.

The changes to SMGs seem to be comprehensive, with accuracy, damage, range, and fire rate all nerfed. The tweaks, which you can see in full below, bring the performance of the SMG and Compact SMG "more in line with where [Epic wants] them." Nevertheless, the studio said it will continue to monitor how the weapons perform and has encouraged players to carry on submitting feedback.