There is a term used by military pilots when they run out of ammunition in the air: "going Winchester." It comes from the Winchester rifle - empty magazine, nothing left to fire. Defense analysts have a politer way to say the same thing: "near-term risk of inventory depletion." The Pentagon is now using that phrase about its own stockpiles, in the middle of a war.

In the first 16 days of Operation Epic Fury - the US-Israeli air campaign that began on February 28, 2026 - American forces used over 6,000 defensive and offensive munitions. That includes, according to the Payne Institute for Public Policy, close to half of the US stockpile of its most advanced precision strike missiles and roughly 40% of its THAAD interceptors. THAAD - Terminal High Altitude Area Defense - is the system designed to shoot down incoming ballistic missiles at altitude before they reach their targets.

The US spent more Patriot interceptors in the first two weeks of the Iran war than Ukraine used defending itself against Russia across the entirety of their conflict with Russia. That single comparison tells you almost everything about the scale of what happened.

The missiles are not coming back quickly. Some of them will take until 2029 to replace.

The Background

To understand why this matters, it helps to understand what a missile actually costs - not just in dollars, but in time.

A cruise missile is a self-propelled, guided weapon that flies at low altitude, using aerodynamic lift to travel hundreds or thousands of kilometers before detonating on a target. The Tomahawk, which the US Navy has fired from ships in the Persian Gulf, has a range of roughly 2,500 kilometers and carries a 450-kilogram warhead. It costs around $2 million per unit. Before the Iran war, the US was procuring roughly 57 to 60 of them per year - partly because of budget decisions, partly because manufacturing one is genuinely difficult.

A ballistic missile follows a high arc through the upper atmosphere, powered only at launch and then essentially coasting down under gravity toward its target. Interceptor missiles - the weapons used to shoot these down - are the most expensive category of all. Hitting a ballistic missile in flight has been compared, for decades, to hitting a bullet with a bullet. The technology now exists to do it reliably, but the hardware is not cheap: a single Patriot PAC-3 missile interceptor costs roughly $4 million.

Iran, by contrast, has been firing modified versions of the Shahed drone - essentially a one-way kamikaze aircraft - that cost somewhere between $50,000 and $80,000 each. The cost asymmetry is real and was obvious well before this war started. Firing a $4 million missile to destroy a $70,000 drone is not a sustainable equation if the drones keep coming.

What was less visible until recently was how thin the US stockpile already was - and how long it takes to build it back up.

Defense procurement - the system by which governments buy weapons from private companies - operates on timelines that have nothing to do with the speed of actual conflict. A contract signed today to produce Patriot missiles will see the first deliveries in roughly two to three years. The factories that make the components for these systems are small, specialized, and in many cases the only facility in the country that makes a particular part. There is one main factory in Tucson, Arizona, that produces Tomahawk cruise missiles. The production of solid rocket motors - the propellant systems that power most missiles - is dominated by two companies in the entire United States.

This is not a secret. It has been flagged repeatedly in congressional testimony, think-tank reports, and post-mortems on the Ukraine war. The system just never got fixed.

What Is Actually Happening

The Odd Lots podcast recorded on March 12, 2026 - roughly two weeks into the war - captured Tom Karako, director of the Missile Defense Project at the Center for Strategic and International Studies (CSIS), describing the situation in unusually direct terms.

"There has been an enormous, and I would say a scary amount of missiles expended on the part of the United States," Karako said. He quoted General Dan Caine, Chairman of the Joint Chiefs, who when asked whether the US had enough missiles, said: "We have enough for this conflict." Karako's point was that this is a very different statement from having enough for everything else.

The numbers have since become clearer. According to a CSIS analysis published in late April, the US had expended at least 45% of its stockpile of Precision Strike Missiles, at least half of its THAAD inventory, and nearly 50% of its Patriot air defense interceptors across the first seven weeks of the war. The Pentagon spent roughly $24 billion worth of major munitions in that period, across seven categories of missile.

After a month of fighting, the US had used over 850 Tomahawk cruise missiles alone. That represents years of stockpile accumulation - the US budgeted for 57 Tomahawks in 2025 and procured 22 of them. The math is straightforward and uncomfortable: the US used in weeks what it builds in years.

Patriot interceptors tell a similar story. CSIS estimates that between 1,060 and 1,430 Patriot missiles were fired during the campaign, representing nearly half of pre-war stockpiles. Replenishment of those interceptors, based on scheduled deliveries and current production rates, is expected to continue until approximately mid-2029. THAAD depletion was even more severe, with some higher estimates suggesting 80% of operational stocks were used.

The war itself appears to have entered a different phase. Karako noted that the rate of Iranian fire dropped sharply after the first days - from hundreds of drones and ballistic missiles per day down to much smaller numbers - as US and Israeli strikes degraded Iranian launch infrastructure. Once Iran's own air defense systems were neutralized, the US was able to shift from expensive long-range Tomahawk strikes to cheaper gravity bombs dropped by aircraft flying directly over targets. That shift, described by the Pentagon as a "munitions transition," preserved some of the remaining high-end inventory. But it does not undo the depletion that had already occurred.

Meanwhile, the US has had to physically move Patriot and missile defense systems from South Korea and Japan to the Middle East - systems whose job is to deter Chinese and North Korean military action in the Pacific. The redeployment was visible in satellite and press photography, and was not subtle.

The Money Trail

The missile shortage is ultimately a story about what happens when a government runs a defense budget like a cost-cutting exercise for three decades and then discovers, mid-conflict, that you cannot manufacture geopolitical deterrence on a just-in-time basis.

The funding gap was documented before the war started. The appropriations bill that became law in February 2026 - the month the war began - included a provision acknowledging that Congress had funded munitions procurement $28.8 billion short of what the Pentagon had actually requested. That shortfall meant the multi-year production contracts needed to actually ramp up manufacturing could not be placed on schedule.

The contracts had been planned. In January 2026, Lockheed Martin signed seven-year agreements to quadruple THAAD interceptor production to 400 units annually and boost Patriot PAC-3 output to 2,000 per year. On February 4, Raytheon signed five framework agreements with the Pentagon to increase Tomahawk production to more than 1,000 units per year, AMRAAM air-to-air missiles to at least 1,900, and SM-6 to more than 500 annually.

These are significant numbers. But they exist in the future. Existing contracts for the PrSM precision strike missile - the successor to ATACMS - call for 54 missiles in 2026, 208 in 2028, and 73 in 2029, for a total of 335 by 2029. The US used multiples of that in the first weeks of the Iran campaign.

The production problem runs deeper than just contract volumes. Karako described a situation where defense companies face contradictory pressures: a single government buyer - a monopsony, meaning one purchaser controlling an entire market - that has historically been unreliable, oscillating between surges and cutbacks depending on which war was active and which politicians controlled the budget. That cyclical demand makes it nearly impossible for companies to invest in long-term capacity. You cannot justify building a second missile factory if you do not know whether the government will buy missiles in three years.

Deputy Defense Secretary Steve Feinberg - who arrived from private equity - attempted to address this by asking defense prime contractors to invest on their own balance sheets in advance of firm contracts. That approach has real limits: publicly traded companies answering to shareholders have difficulty justifying billions in speculative capital expenditure on weapons that may or may not get ordered.

The solid rocket motor problem is its own bottleneck. Two companies - L3Harris, which holds a stake in Aerojet Rocketdyne, and Northrop Grumman - dominate this critical input. The Biden administration had invested $216 million into Aerojet's facility in Arkansas. That investment, now several years old, has not yet produced the capacity needed. New startup entrants into solid rocket motor production exist but remain small. The time from investment to meaningful production volume is measured in years, not months.

The total cost picture goes well beyond the price of the missiles themselves. Moving an aircraft carrier strike group from the Atlantic to the Persian Gulf burns enormous quantities of jet fuel. Aircraft conducting strike missions need maintenance cycles. Bases require repair after being hit. These costs, Karako argued, will dwarf the per-unit cost of the munitions actually fired.

What People Are Doing About It

CSIS concluded in a May 2026 follow-up analysis that the US will require multiple years to replenish key missile inventories, with particular concern about readiness in the Indo-Pacific should a conflict involving China emerge before those stockpiles are restored.

Congress is expected to pass a supplemental defense appropriations bill to fund emergency restocking. The baseline for that conversation is now set by the Iran war's consumption figures, which have given budget negotiators a concrete number to argue over.

Allied supply chains are also under strain. Eighteen countries operate the Patriot missile defense system globally. The Biden administration had already suspended Patriot deliveries to partner nations to redirect supplies to Ukraine. That queue of unfulfilled orders has now gotten longer, not shorter. Denmark recently chose to buy a French air defense system rather than Patriot - not because the French system is better, but because the Patriot delivery schedule was simply too far out.

Ukraine, strikingly, has moved in the opposite direction from most Western countries. By early 2026, Ukrainian firms were producing up to 1,000 interceptor drones per day, and by February these drones accounted for 70% of Shahed intercepts in the Kyiv region. One Ukrainian manufacturer alone plans to produce more than 3 million low-cost first-person-view military drones in 2026, compared to just 300,000 built by the US in all of 2025. Ukraine - operating under genuine existential pressure for four years - built an industrial system that the US, with its vastly larger economy, has not yet managed to replicate.

A deal is now being shaped for the US and Ukraine to jointly develop and build the kinds of weapons that have proved most effective in both the Ukraine and Iran conflicts. That cooperation, if it materializes, represents an acknowledgment that America's defense industrial model needs to learn something from a country it has spent four years supplying.

The military itself has adapted within the current war. The shift from expensive standoff strikes to cheaper gravity bombs - once Iranian air defenses were destroyed - shows that the "munitions transition" is real. But it required first destroying an adversary's air defense network, which itself consumed a large portion of the inventory now missing.

The Bottom Line

The Iran war did not create a missile shortage. It revealed one that was already there. The US has spent decades designing exquisite, expensive weapons and procuring them in quantities calibrated to peacetime politics rather than wartime consumption. The Ukraine war made the problem obvious in theory. The Iran war made it obvious in practice - burning through in weeks what the defense industrial base produces in years, while the contracts for fixing that pipeline were signed the same month the shooting started. The question now is not whether more money will be committed to missile production. It almost certainly will be. The question is whether the factories, the workforce, and the supply chains can actually convert that money into hardware before the next conflict starts.

Timeline

  • 2014-2022 - The Ukraine conflict and subsequent full-scale Russian invasion reveal Western munitions stockpiles are calibrated for short wars, not sustained high-intensity conflict
  • April 2025 - The US Army quadruples its objective acquisition target for Patriot PAC-3 missiles, from roughly 3,000 to 13,000 units
  • Memorial Day 2025 - Deputy Defense Secretary Steve Feinberg begins meeting with defense CEOs to accelerate production planning
  • Summer 2025 - The 12-Day War between Israel and Iran depletes US and Israeli interceptor stockpiles; a ceasefire is announced
  • January-February 2026 - Lockheed Martin signs seven-year contracts to quadruple Patriot and THAAD production; Raytheon signs five framework agreements to boost Tomahawk and AMRAAM output
  • Early February 2026 - The US appropriations bill for FY2026 becomes law, with Congress acknowledging a $28.8 billion shortfall in Pentagon munitions funding
  • February 28, 2026 - Operation Epic Fury begins; US and Israeli forces strike Iranian leadership and military sites
  • March 12, 2026 - Bloomberg's Odd Lots podcast records Tom Karako of CSIS describing "a scary amount" of missile expenditure and warning of stockpile depletion
  • March 27, 2026 - Small Wars Journal analysis reports that at the early-war rate of consumption, the US could deplete three key munition categories within a month
  • April 21, 2026 - CSIS publishes its first stockpile assessment, confirming depletion of at least 45% of Precision Strike Missiles, half of THAAD inventory, and close to half of Patriot interceptors across seven weeks of war
  • May 12, 2026 - Senator Mark Kelly, a former Navy pilot, publicly raises the stockpile question; Pentagon pushes back
  • May 27, 2026 - CSIS follow-up analysis concludes the US will need multiple years to rebuild its missile inventories, with Patriot replenishment expected to continue until mid-2029

Summary

Who: The US Department of Defense, defense contractors Raytheon (RTX) and Lockheed Martin, CSIS defense analysts, and allied nations operating US-supplied missile systems

What: The Iran war has consumed an estimated 45-50% of several key US missile categories - including Patriot interceptors, THAAD missiles, and Precision Strike Missiles - in a matter of weeks, depleting stockpiles that will take years to rebuild under current production rates

When: Operation Epic Fury began February 28, 2026; the depletion problem has been accumulating since at least 2022 and the Ukraine conflict

Where: The Persian Gulf and Iran theater, with knock-on effects for US readiness commitments in South Korea, Japan, and the Pacific

Why: Decades of cyclical, politically-driven defense procurement produced stockpiles sized for short wars; the Ukraine and Iran conflicts have shown that modern high-intensity conflict consumes missiles far faster than peacetime production can replace them