The U.S. has an estimated inventory of around 20 GBU-57 Massive Ordnance Penetrator (MOP) bunker buster bombs, which are the largest non-nuclear bunker-busting bombs in its arsenal. These bombs weigh about 30,000 pounds each and are designed to destroy deeply buried and heavily fortified underground facilities. The exact number is not officially confirmed, but estimates and reports suggest the stockpile is in the vicinity of 20 units. For example, in June 2025, the U.S. reportedly used 14 of these bunker busters in a military operation against Iranian nuclear facilities, which represented a significant portion of the U.S. inventory. The MOP bombs can only be delivered by B-2 stealth bombers, and the U.S. has about 19 of these bombers capable of carrying the bombs. This bomb is uniquely powerful and requires specialized deployment means, making the U.S. the only country with this specific capability in operational stockpile, according to recent confirmed sources.
