What is the GBU-57A/B 'Bunker Buster' Bomb? 30,000-Pound Non-Nuclear Weapon US May Use Against Iran

The GBU-57A/B 'Bunker Buster' is the US's most potent non-nuclear bomb, weighing 30,000 pounds and designed to penetrate 200 feet of hardened targets. It's considered the only weapon capable of hitting Iran's deeply buried Fordo nuclear site. (Credit: Gage Skidmore/Flickr / Creative Commons)

The United States deployed its most formidable conventional weapon —the GBU-57A/B 'Bunker Buster' bomb or Massive Ordnance Penetrator — in 22 June 2025 strikes against Iranian nuclear facilities.

This colossal 30,000-pound bunker-buster bomb achieved its first-ever operational use during Operation Midnight Hammer, when seven B-2 Spirit bombers delivered 14 of these weapons against Iran's most fortified nuclear sites.