How can a fiberglass tub stop a bullet? They are pretty thin. I don't think any tube will stop something the size of 9mm or bigger. The old Cast Iron clawfoot tubs probably stand the best chance of deflecting a bullet or at least absorbing enough to where they would penetrate very deep. I do know for a fact a toilet will not stop a bullet, and creates a whole lot of shrapnel in the way of tiny bits of sharp ceramic.
That was with a .45 though, it was fun