I made a sample project. All of the things that i created for it are in the Content folder. The only other things that I edited were the FirstPersonCharacter and FirstPersonGameMode blueprints located in the default firstpersonBP folder. There are many examples of referencing the gamemode blueprint in there. And no need to keep resetting variables every time you enter the turret! I’ve set up a turret for you to possess, some ammo to pickup, a system that checks your ammo count when you try to shoot, and an object that hurts you so you can see that it retains health as well when the player is re-spawned.
The attached project is linked below Using Unreal 4.18.2
If you have questions feel free to ask!