Mounted Turret was a Legendary trap item in Battle Royale. It is a turret machine that can be only placed on floors and has unlimited ammo, but will overheat if fired too often. Once placed, it can be used by any player regardless of team affiliation and can be also damaged by shooting it directly or by destroying the structural support.
The Mounted Turret was vaulted on Patch 10.00, making it currently only available in Playground and Creative. It was most likely vaulted due to being very overpowered and having lots of glitches with it.
Mounted Turret can be dropped by zombies in the Storm King LTM.
Over time, we have added many mobility options, both itemized and map-based. We feel that Season X is better experienced with a reduction in mobility. As with all changes, we’ll keep a close eye on how this affects the player experience.