B61-11 Explained: The Nuclear Bunker Buster Behind Carlson’s Pickaxe Claim
The B61-11 is the only U.S. nuclear bomb built to burrow before it explodes. Analysts say it fits targets like Pickaxe Mountain, which Tucker Carlson claims Trump may strike.
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The B61-11 is the only U.S. nuclear bomb built to burrow into the ground before it explodes. Analysts say it is the weapon designed for targets like Iran’s Pickaxe Mountain.
The bomb is back in the news. Commentator Tucker Carlson claimed on X that the White House could be days from a nuclear strike on Pickaxe Mountain. Our report on his claim covers the details.
Carlson never named the B61-11. The link is analysis, not his statement. Washington and Israel have not confirmed his claim.
What Tucker Carlson Claimed
Carlson posted early on Nov. 2 that the administration “may be within days of launching a nuclear strike on Iran.” He cited an unnamed “informed observer.” He offered no documents.
He wrote that no conventional weapon can penetrate 300 feet of granite. “The only military option is a nuclear strike,” he wrote. He said Trump may decide by Nov. 7.
Trump said on Newsmax on Oct. 15: “No, I wouldn’t use nuclear. We don’t have to.” He said the “mother of all bombs” is not nuclear.
Nothing public shows a decision. Treat the claim as unverified, and read this guide as background on the weapon.
What the B61-11 Is
The B61-11 is a nuclear gravity bomb with a hardened casing and a delayed fuze. It is a modification of the B61 family, which dates to the 1960s. The Bulletin of the Atomic Scientists says it was converted from the B61-7.
It entered service in 1997 and replaced the megaton-class B53 in the bunker-busting role. About 50 were produced. It weighs about 1,210 pounds, according to a National Research Council report.
Its yield is not public. The Nuclear Weapon Archive suggests it matches the B61-7, up to about 340 kilotons. The Bulletin of the Atomic Scientists lists 400 kilotons.
Russia’s Kosvinsky Kamen command bunker is one proposed reason for the bomb. It was finished in 1996 under about 1,000 feet of granite. Some analysts see the timing as a clue.
How an Earth-Penetrating Nuclear Bomb Works
A normal nuclear bomb detonates in the air or on the surface. Much of its energy goes into the atmosphere. A penetrator digs in first, so more energy shakes the ground.
The National Academies say a nuclear penetrator reaching about 3 meters captures most of the ground-shock advantage. That cuts the yield needed to destroy a deep target by a factor of 15 to 25. See the National Academies findings.
The B61-11 does not drill hundreds of meters. The Air Force says its new case lets it reach 15 to 25 feet before detonation. Its tests in Alaska reached 6 and 10 feet into frozen soil.
The effect is a shock wave through the rock. It can collapse tunnels far below the crater. The weapon does not need to reach the target itself.
Sandia National Laboratories filmed this B61 flight drop test at the Tonopah Test Range. Sandia does not identify the B61-11 in it. It shows how the family is tested.
Testing and Delivery
A B-2 Spirit dropped two B61-11 test casings in Alaska on March 17, 1998. The Air Force called them the final tests needed to certify the bomb. The B-2 remains the main carrier, as our B-2 Spirit explainer shows.
The National Nuclear Security Administration flew a B61-11 test assembly from a B-2 in 2011. It carried no nuclear material. In 2013, Sandia fired a B61-11 test unit by rocket into a concrete target.
Why Pickaxe Mountain Is Named in the Debate
Pickaxe Mountain, or Kuh-e Kolang Gaz La, sits just south of Natanz. BBC Verify says analysts estimate its core could be roughly 100 meters down. See the BBC explainer.
The Institute for Science and International Security estimates the site is at least 100 meters deep. Israel believes Iran moved centrifuges there, we reported. Iran says no nuclear activity takes place there.
Analysts say this is where the B61-11 enters the debate. The National Academies calculated that a 300-kiloton penetrator could severely damage tunnels in granite down to about 150 meters. They put the outer limit for destroying hard targets at about 200 meters.
That is a theoretical model, not a prediction for Pickaxe. The real depth, rock and layout are unknown. The B61-11’s yield is also not public.
Hegseth told senators on July 21 that the U.S. military can reach “anything on God’s green Earth.” He did not say how.
B61-11 vs GBU-57
The U.S. conventional answer to deep sites is the GBU-57 Massive Ordnance Penetrator. It weighs about 30,000 pounds. The BBC says it can reach about 18 meters of concrete or 61 meters of earth.
| B61-11 | GBU-57 MOP | |
|---|---|---|
| Type | Nuclear penetrator | Conventional penetrator |
| Weight | About 1,210 lb | About 30,000 lb |
| Penetration | 15 to 25 ft (Air Force) | About 61 m of earth (BBC) |
| Yield | Not public | Conventional explosive |
| Carrier | B-2 Spirit | B-2 Spirit |
| Combat use | None | June 2025 |
The MOP digs deeper, but it carries far less energy. The B61-11 digs only a few meters. Its power comes from the nuclear yield and the shock it sends into the rock.
BBC Verify quotes experts who say even MOPs would be unlikely to destroy Pickaxe completely. They say strikes on entrances, vents and roads could still disable it.
This 509th Bomb Wing footage, republished by The Aviationist, shows a B-2 releasing two GBU-57s.
B61-12 and B61-13
The B61-12 is a life-extension rebuild with a guided tail kit. It is replacing the B61-3, -4 and -7. Open sources say its casing lacks the Mod 11’s penetrator hardening.
The B61-13 is a new high-yield, guided variant. The first unit was completed in May 2025. The National Nuclear Security Administration plans only a few dozen.
The B61-11 stays in the stockpile for the penetrator role. Former Air Force chief Norton Schwartz said in 2014 it lands within about 110 to 170 meters.
Limits and Fallout
A shallow burst does not contain a nuclear explosion. The National Academies say penetrators cannot reach the depth for full containment. They say casualties match a surface burst of the same yield.
For remote sites, they estimate casualties from hundreds to hundreds of thousands. That depends on yield and wind. Fallout would spread over a wide area.
Using any nuclear weapon would break a taboo held since 1945. Trump has said he would not use nuclear weapons on Iran. No official has said the B61-11 is under consideration.
B61-11 FAQ
What is the B61-11? A U.S. nuclear gravity bomb with a hardened casing. It is built to detonate underground.
Has it ever been used? No. It has only been tested with inert or mock components.
How deep does it go? The Air Force says 15 to 25 feet. Alaska tests reached 6 to 10 feet in frozen ground.
Can it destroy Pickaxe Mountain? Nobody knows. Models suggest a large yield could damage tunnels near 150 meters. The true depth is unknown.
Did Tucker Carlson name this bomb? No. He said only that a nuclear strike was the sole option.
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