US Army Rebuilds Domestic Antimony Supply in Idaho After Losing China Source

The US Army is establishing domestic production of antimony sulfide — the critical ingredient in ammunition primers — in Idaho, after Chinese supplies ceased in 2021. Full production at Stibnite is set for late 2028.

At a Glance

Antimony sulfide lets ammunition primers fire reliably across extreme temperature ranges.
The US lost access to Chinese antimony sulfide in 2021.
Partners: the Army, Perpetua Resources and Idaho National Laboratory; a prototype facility is already running demonstrations.
Raw antimony sulfide production is planned at Stibnite, Idaho; full production by late 2028.
Part of the Army’s “Ground-to-Round” end-to-end domestic supply chain strategy.

The Critical Ingredient in Every Primer

Antimony sulfide is what makes a cartridge primer fire reliably from arctic cold to desert heat. The United States sourced it from China until shipments ceased in 2021, exposing one of the sharpest vulnerabilities in the American ammunition chain.

The Army’s Agile Sustainment and Ammunition portfolio, working with Perpetua Resources and Idaho National Laboratory, has answered with domestic production: a prototype facility is operational for demonstrations, and full raw production at the Stibnite site is scheduled for late 2028.

“Ground-to-Round”

The project belongs to the Army’s Ground-to-Round strategy — building every link of the chain from raw material to finished round inside the United States, alongside mineral processing facilities and munitions production lines at installations across multiple states.

Critical mineral dependence now sits at the center of defense planning: China’s export restrictions on gallium, germanium and antimony have triggered a cascade of similar onshoring programs across the West.

Why It Matters

Antimony looks like a minor primer ingredient; in fact it is a precondition for all ammunition production. Rebuilding the chain from mine to primer shows that critical-mineral security has become synonymous with ammunition security.