Anyone know if its safe or realtivly safe to use "unrated"(as in that the store-clerk is clueless) half-hard copper-pipe for a Pneumatic pistonvalve marblelauncher. The reason for a n00b question like this is because i live in Sweden and Pressure-rated copper and PVC -pipe is for some stupid reason ...

I read somewhere that ABS plastic is best because it rips rather than shatters when the pressure get to high.