Board Thread:Fun and Games/@comment-30510141-20161220114724/@comment-25856498-20161220122834

A Silver Chest has a lower chance of containing a Rare or Epic card than a Free Chest does.

For Rares, it's 1 in 12 and for Epics, it's 1 in 500.

On the other hand, a Free Chest has 1 in 10 cards contain Rare and 1 in 200 cards contain an Epic.