Did you do this to shave weight? And if so, how much did it take off?
It was to save/shave weight. I calculated the weight savings beforehand, so I wasn't surprised by the results - it was a little over a third of a pound, which, in that case, brought the bass I have with the heaviest body into line with the others. That bass is now about 7.5 pounds (as heavy as any I play standing up).
Chambering (either open or closed chambers) by itself won't take a heavy bass and make it a lightweight. To make a light bass, every piece - hardware (including things like the neck plate and knobs), wood, even the presence or absence of a pickguard - every piece has to be chosen to make the final result what you want.
