The GBU-57 is a big fat gravity bomb with fins. To achieve effective precision, a B-2 bomber must drop it on its intended target from no further than about five nautical miles — essentially right on top of the target.Its penetration depth is claimed to be 200 feet. But that capability has NEVER been tested against a seriously hardened deep-underground target encased in layers of high-performance concrete, and topped with a few dozen meters of solid rock. In that sort of real-world scenario, the GBU-57 would be lucky to drill down 50 feet, if that.
