$UAMY

Antimony is a critical component used in armor-piercing rounds, bullet cores, tracer rounds, explosives, and military equipment, especially as a flame retardant. If the war with Iran drags on, U.S. ammunition production would likely ramp up quickly, which could directly increase demand for the antimony produced by UAMY.
Antimony is not used only in infantry rifle ammunition. It is also a critical component in the primer capsules of Tomahawks, Patriot interceptor missiles, and air-to-ground smart munitions such as JDAMs, as well as in certain specialized warhead formulations. Even more importantly, small but vital amounts of antimony are used in the production of the microelectronic components inside the guidance systems of these missiles, especially in semiconductor doping processes. As the inventories of these multimillion-dollar missiles are depleted, Pentagon pressure to replenish those stocks quickly could create sudden spikes in raw material demand, effectively a supply shock.
In military aviation, antimony trioxide is a difficult to replace standard flame retardant for the wiring, avionics systems, and structural composite materials used in aircraft. The ability of aircraft to operate under extreme conditions without burning depends on this chemical structure.
If the war drags on, the U.S. government could activate mechanisms such as the Defense Production Act to protect domestic critical mineral producers and expand their capacity. That could come back to UAMY in the form of government support, grants, or long-term purchase guarantees.
On the other hand, even though antimony is not a rare earth element, it is often evaluated within that same basket. If the Trump administration reaches an REE, or more broadly a critical minerals, agreement with China that eases supply chains, UAMY could be negatively affected.