New US B61-13 gravity bomb nears completion, set to outpace initial timeline

On May 7, Teresa Robbins, acting head of the US National Nuclear Security Administration (NNSA), informed the House Armed Services Strategic Forces Subcommittee that the first production unit of the B61-13 gravity bomb is expected to be completed later this month, significantly ahead of schedule.

Robbins shared that the program was progressing nearly a full year ahead of its planned timeline, noting that the B61-13’s first production unit was initially slated for completion in fiscal year 2026, according to the 2025 Stockpile Stewardship Management Plan (SSMP) released by the NNSA in October.

The SSMP further projects that the full production of the B61-13 will conclude in fiscal year 2028. However, an NNSA spokesperson confirmed in April that the agency expects to finish the first production unit of the bomb by fiscal year 2025, marking a significant acceleration of the timeline.

The spokesperson attributed this fast-tracking to leveraging manufacturing processes from the B61-12 program, which saw its final unit completed in 2024, along with the introduction of technical innovations designed to optimise production. Robbins reiterated this point during her testimony, emphasising that an "existing production line" had been used to expedite the process.

The B61 family of bombs, currently deployed by both the U.S. Air Force and NATO bases, is the oldest nuclear weapon in the U.S. arsenal, with over 50 years of service. The B61-13, in particular, is a gravity-delivered nuclear bomb with a yield of 360 kilotons, according to the Federation of American Scientists. This makes its explosive power 24 times greater than the bomb dropped on Hiroshima in 1945.

While the B61-13’s devastating potential is notable, it faces competition from more powerful weapons such as Russia’s RS-28 Sarmat, which carries warheads twice as destructive, and China’s DF-41, which is capable of targeting multiple locations at once.

In contrast to Russian and Chinese missile-based warheads, the B61-13 will be delivered via aircraft. Initially, it will be deployed from the stealthy B2 bomber, with future deliveries planned for the B-21 Raider, expected to enter service by 2030.

The production of the B61-13 bomb was first initiated under the Biden administration, which justified the project in 2023 by stating it would serve to replace all existing nuclear gravity bombs in the U.S. arsenal.