I just saw this video of 6 or 7 big strong dudes with crowbars, sledgehammers, and axes being completely unable to break into a gun safe:
That is one strong safe. The guys totally think they have it in the bag for about the first five seconds, until they discover that it just rolls around whenever they try to get any leverage. It just goes downhill from there. I would totally get one if I had the moolah.