Thanks to the WSJ, I can now impress my friends with all sorts of stats and tidbits about the GBU-57, the 30,000-pound ‘Massive Ordnance Penetrator,’ aka the ‘Bunker Buster’ bomb. … And use of the GBU-57, not to be confused with the GBU-28C, is considered only the ‘best chance’ of destroying Iran’s nuclear facilities. … More GBU-57 stats, including total AFX-757 and PBXN-114 polymer-bonded explosive payloads, at Wikipedia.

Update — 6.20.25 – Via the Guardian, here’s more on whether the Bunker Buster would even work or not.

Update II— 6.23.25 – Two days after the U.S. attack on Fordow, there’s apparently little doubt the Bunker Buster’s inflicted heavy damage on the facilities, but it’s not clear whether the facilities were completely destroyed, the NYT reports. … Meanwhile, it appears Iran was rushing to evacuate materials out of Fordow in the days before the bombings, as CNBC reports.