Originally Posted by SpikedGhost
I spoke to someone that works a lot with metal and he told me that on some scale (depending on the surface) any kind of friction between glass and metal will put some "wear" on the metal since glass is harder than most metals. Also some grinding discs (for metal) are made with glass powder. I might be wrong, but I think after continuous use, they will degrade your tightbore much faster than normal BBBs. I was bummed out when I heard this since I was really looking forward to using them. Again I might be wrong about this and a lot more research on this subject should be done.
Correct me if I'm wrong, but the BBs doesn't touch the barrel. The BB is surrounded by air.