The National Nuclear Security Administration (NNSA) said it has completed “diamond stamping” of the new B61-13 nuclear bomb, meaning it met all requirements of the rigorous certification process.
The US National Nuclear Security Administration (NNSA) announced June 8, 2026 the “diamond stamping” of all Canned Subassemblies (CSA) of the new B61-13 gravity nuclear bomb. The milestone was reached “three months ahead of schedule” at the Y12 National Security Complex located in Oak Ridge, Tennessee.
The NNSA explained in a press release that “‘diamond stamped’ means that a weapon component has met all requirements of the NNSA’s rigorous certification process and is approved for deployment in the US nuclear arsenal as ‘war reserve’ quality.” The milestone also comes just over a year after Sandia National Laboratories (SNL) unveiled the first joint test assembly (JTA) of the B61-13 in March 2025, and the first complete bomb unit a few months later in May 2025.
The NNSA explained that the CSA component in a modern two-stage thermonuclear weapon includes the secondary stage capsule and “other parts sealed (canned) inside a thin metal container made of stainless steel or aluminum alloy.” This is combined with the primary stage – the nuclear explosive package of the warhead.
🚨NNSA has completed “diamond stamping” of all B61-13 nuclear gravity bomb (CSA) canned subassemblies planned for the current fiscal year, three months ahead of schedule in @y12nsc.
This first milestone underscores our commitment to meeting President Trump’s national goals… pic.twitter.com/BH90dCktTz
— NNSA (@NNSANews) July 8, 2026
The B61-13 has been described as a “modern variant of the B61 nuclear bomb, the most versatile and longest-lasting weapon in the United States nuclear arsenal.” The new bomb is designed to “defeat hard, deeply buried targets” and will be certified to be dropped by US Air Force strategic bombers, including the new B-21 Raider.
The B61-12 Life Extension Program (LEP) and production of the new B61-13 are being carried out in a manner that does not change the number of gravity-delivered nuclear bombs in the United States inventory. As we explained in a previous report on the B61-12 LEP in January 2025, the B61-13 will replace some of the B61-7s in the current arsenal and the number of B61-12s to be produced will be reduced by the same amount as the number of B61-13s produced.
Important milestone
In the news release, NNSA Administrator Brandon Williams said progress on the B61-13 program demonstrates the Nuclear Security Enterprise’s “ability to respond to evolving geopolitical requirements with speed and precision.” Williams further added that “completing the 2026 baseline deliverables ahead of schedule is a clear indicator of discipline and operational focus” and “sends a message to our adversaries that our national defense remains agile, secure and effective.”
Furthermore, a separate update on SNL website reported 32 flight tests of inert weapons across the nuclear triad. These included “a W80 air-launched cruise missile test,” conducted at the Utah Test and Training Range, and two B61-13 “ground penetrating weapons.”
The agency generically mentioned “flight and ground testing,” but it is unclear whether the B61-13 also underwent drop testing. Furthermore, the mention of the W80 warhead suggests a test of the W80-1 warhead of the AGM-86 air-launched cruise missile (ALCM), or the W80-4 intended for the AGM-181 long-range missile (LRSO).
B61-13
The B61-13 uses the warhead of the older B61-7, which had a yield ranging from 10 to 360 kt, but also features improved safety and precision mechanisms and improved components. The B61-13 will reportedly have higher and lower performance options, from 0.3 to 1.5 kt, and from 10 to 50 kt.
It was my honor today to seal the first complete B61-13 unit in the @PantexPlanta!
This achievement signals to both our adversaries and allies that the United States is prepared to meet the challenges of today’s environment from a position of strength and security. pic.twitter.com/1kgT3OF5Fa
— Secretary Chris Wright (@SecretaryWright) May 19, 2025
A specific feature of the B61-13 is the ability to attack underground targets with “limited ground penetration capabilities.” […] through soft ground”, according to the Federation of American Scientists (FAS). After hitting buried targets, the B61-13 can explode with “yield equivalent to a more than one megaton surface explosion weapon.”
An F-35A flying at supersonic speed conducted a drop test of the new B61-12 guided nuclear bomb. The first in a series of tests to certify that the F-35A is capable of delivering the B61-12. https://t.co/mM3yNVeGBE Some 480 B61-12s will arm US and NATO aircraft. pic.twitter.com/CzMAj8BO4p
— Hans Kristensen (also on Bluesky) (@nukestrat) November 23, 2020
Like the B61-12, the B61-13 will also undergo grueling stress, shock, pressure, vibration, impact and environmental tolerance tests to evaluate that the pump and its individual parts are performing as planned. These include being fired from a Davis Pistol operated by SNL in an 8-foot-deep pool, a Forward ballistic impact test on a track on high-speed rails and, finally, tests from several airplanes.
Currently, the B61-13 is intended for use only by the B-21 Raider stealth bomber.
B61-12 Forward ballistic impact
Source: Watermelon pic.twitter.com/Sm1LRsy6oq— Casillic (@Casillic) November 10, 2023
Development of the new weapon was first publicly announced in October 2023. In March 2025, SNL revealed the first joint test set (JTA) of the B61-13, a test article without the active nuclear warhead for various ground tests as well as captive transport and standoff aerial tests.
In May 2025, the NNSA announced the production of the first B61-13 nuclear bomb at the Pantex plant in Amarillo, Texas. This came almost a year before “the original planned date and less than two years after the program was announced, making the bomb one of the most rapidly produced nuclear weapons after the Cold War,” according to the statement.
B61-12 Forward ballistic impact
Source: Watermelon pic.twitter.com/Sm1LRsy6oq— Casillic (@Casillic) November 10, 2023
In the latest press release, the NNSA highlighted: “The newest variant features increased nuclear yield, aimed at defeating certain tougher, large-area military targets, providing additional flexibility to the President’s nuclear response options. The B61-13 is one of six ongoing warhead modernization programs that the NNSA is executing to ensure the long-term reliability and effectiveness of the United States nuclear weapons arsenal.”
