I found a glitch on Sandtrap, where you can get on the left turret on the elephant, break it off, and the turret will immediately respawn. Then get back on it, and repeat it until you might overload the map. I haven’t tested if it can really overload, though.
You can also overload the map in Forge. If you place trip mines where you spawn, set the spawn time of them to 1, and throw them into a big pile, once filled, they will eventually explode (or player triggered) and the turrets won’t shoot when out of bounds.