Board Thread:Game Discussion/@comment-9971098-20130622022342/@comment-9477730-20130624224418

You can absolutely get R4 from metals. All of the elite cards can only be obtain either by the bridge or metals.

Although it takes 1000-2000 metals to find one R4. (which is 0.05%-0.1%).

I don't know the drop rate of a raid card, but it's a lot lower than just getting a R4. (I haven't found one yet in 6 events through opening metal)