Thin, cheapo shells, definitely won't survive that. The glued together bb's separate about 50% of the time, so exit the gun as 4 separate bb's. Unfortunately this means 50% of the time they stick together, which very much defeats the purpose. I've talked to a friend who thinks it might be possible to adjust the O-rings I've bought to the perfect size if I freeze them so they're rigid, then sand them down.
EDIT: Also thinking about putting a link to this topic in technical discussion, maybe get some more ideas on how to do this.