saw a bar table ball break many years ago
I saw a bar table cue ball break many years ago. It had a section of pipe or tubing in it reaching almost side to side of the cue ball. Like this, it didn't look like it would balance. Apparently the weight of the metal and the cue ball material isn't that much different, I don't remember an issue with a bar table cue ball rolling bad. Too long ago, I don't remember if it was a Valley cue ball or a replacement that broke.
I have played with one of the deliberately weighted balls a bunch of times but it never broke so I never saw inside it to know how it was weighted to roll bad. The surprise is how they get these to roll straight.
Hu