TrainShot electronic unit is protected by steel Hardox 600, so practicaly it is bulletproof. You can also buy additional shield made of polycarbonate. Guys are developing now an extender to protect the unit, because TrainShot unit is bulletproof, but not shockproof. They shot directly to unit I think 5 times and unit saved, but LED part was damaged. But they are selling also this part, so when you accidentaly shoot to unit and LED part would be damaged, it can remove it easily. Guys give on their e-shop preety good support for this product, I think.
What have you done with that peice of metal to keep the shooter safe from ricocheting rounds and fragments?