The Replenishment Gap: Peacetime Efficiency and Strategic Redundancy in American Munitions Production

Introduction

Recent conflicts have exposed a persistent constraint on American military preparedness. Munitions can be expended more rapidly than the industrial base can replace them. Russia’s full-scale invasion of Ukraine generated sustained demand for artillery ammunition and guided weapons, both to support Ukraine and to replace munitions transferred from American stocks. United States operations against Iran in 2026 placed additional pressure on high-end missiles and interceptors. These demands have emerged in succession. The problem is therefore not simply whether the United States possesses sufficient inventories at the outset of a crisis, but whether those inventories can be restored before further strategic demands arise. By March 2024, Congress had provided $25.9 billion in supplemental funding to replace weapons transferred to Ukraine, with more than $2.8 billion of this funding committed or obligated to expand production (U.S. Government Accountability Office [GAO], 2024). Large procurement requests following operations against Iran nevertheless coexist with projected delivery schedules measured in years (Cancian & Park, 2026).

This article describes the resulting disjunction as the replenishment gap. The term refers not simply to inadequate inventories, but to the interval between a government decision to fund replacement and the arrival of additional, operationally usable munitions. The strategic concern is whether replenishment can proceed quickly enough to restore the stocks required for subsequent commitments. Crisis funding can expand output, as the growth of American 155 mm artillery shell production after 2022 demonstrates. Its effects are nevertheless conditioned by the state of the industrial base when the crisis begins. Production lines that remain active, retain qualified workers and have access to established suppliers can respond more readily than those requiring the redesign of obsolete components and the rebuilding of a skilled workforce (Loidolt, 2025).

The relevant policy question is therefore how American procurement should preserve and verify the replenishment capacity required under sustained strategic pressure. This article argues for selective strategic redundancy rather than a general return to permanent mobilisation capacity. For munitions characterised by high expected consumption, long production lead times, concentrated suppliers and continuing relevance across theatres, the United States should combine minimum sustaining orders with reserved capacity, critical-input buffers and periodic production tests. Such arrangements could reduce both the duration and uncertainty of the lag between funding and output, while making continued government funding conditional on demonstrated production capability.

Peacetime Efficiency and Strategic Redundancy

The ability to expand munitions production depends on procurement decisions made before demand increases. Defence production operates in a market where governments are the principal purchasers, entry barriers are substantial and many weapons depend on a limited pool of qualified suppliers. Procurement policy consequently shapes not only what the state buys, but also which industrial capabilities firms have incentives to maintain (Rogerson, 1994). Maintaining spare capacity may be commercially difficult to justify, even when it would enable faster replenishment during a crisis.

When procurement is limited to current requirements, firms incur additional costs by retaining spare equipment, a larger skilled workforce and qualified alternative suppliers, while future orders may be too uncertain in scale or duration to warrant this expenditure. The Army Science Board (2023) identifies inconsistent demand, interrupted production and delayed investment decisions as constraints on American munitions expansion. Case studies of four Swedish defence firms also highlight cost pressures, demand uncertainty and insufficient incentives to maintain additional capacity (Hellberg et al., 2025). Without sustained purchasing commitments or payments for maintaining capacity, reducing these costs can therefore be commercially rational, even though it limits the ability to expand production when demand rises.

Earlier American experience illustrates the importance of the assumptions underlying capacity planning. A 1996 GAO report described defence planning based on regional conflicts lasting 60 to 120 days, supported by existing stocks without significant production expansion during hostilities. The industrial base was expected to replenish stocks after the conflicts had ended (U.S. General Accounting Office, 1996). A later episode illustrates the difficulty of adjusting to changing demand. Between 2000 and 2005, small-calibre ammunition requirements increased from approximately 730 million to nearly 1.8 billion rounds, driven substantially by expanded training needs alongside operational deployments. Despite investment in government-owned plants, domestic capacity remained insufficient, and foreign commercial suppliers helped meet the shortfall (GAO, 2005). These reports do not establish that earlier planning decisions alone caused the later supply constraint. They nevertheless illustrate why the ability to meet increased demand depends on both existing capacity and the time required to expand it. Retaining selected capabilities in advance may reduce the delays associated with this expansion.

Strategic redundancy should therefore be understood as a selective investment in replenishment capacity, rather than a general rejection of efficiency. The policy trade-off is between the recurring cost of maintaining capabilities and the risk that their restoration will take longer than strategic circumstances allow. Equipment that appears underused in commercial accounts may retain value by reducing that risk. Yet excess capacity can also protect incumbent contractors and sustain facilities for political rather than strategic reasons (Gholz & Sapolsky, 1999). Supply-chain resilience requires a balance between vulnerability and the cost of additional capabilities, rather than the unrestricted expansion of spare capacity (Pettit et al., 2010). The purpose is not to preserve every existing production line, but to maintain capabilities whose loss would create unacceptable replenishment delays. This distinction becomes more consequential when successive crises place demands on the same industrial base before depleted stocks have been restored.

Consecutive Pressures on the Same Industrial Base

Overlapping commitments increase the cost of replenishment delays by leaving less time to restore stocks before further demands arise. The Army Science Board (2023) warned that efforts to replace munitions supplied to Ukraine would not necessarily provide the industrial capabilities needed for an Indo-Pacific contingency. Replenishment policy therefore needs to consider both the recovery of depleted inventories and the composition of future demand. Higher aggregate output is insufficient if expansion is concentrated in weapons that cannot meet other anticipated operational needs. Procurement planning should identify which capabilities can support commitments that may arise before existing replacement programmes are complete.

The pressure on production increases where several commitments draw on the same munition. For Patriot interceptors, Cancian and Park (2026) identify competing demands from American stock replacement after operations against Iran, continued support for Ukraine and orders from other partners. Because production of the PAC-3 Missile Segment Enhancement (MSE) variant serves both American and foreign customers, increased output does not translate directly into an equivalent increase in American stocks. Domestic replenishment therefore depends not only on total output but also on how deliveries are allocated. Prioritising American stocks may accelerate their recovery, but at the cost of postponing deliveries intended to strengthen partners’ defences. These allocation decisions also need to account for Indo-Pacific preparedness, although planning for such contingencies does not imply that another conflict is inevitable.

Longer purchasing commitments can support the industrial expansion needed to meet these demands, yet they do not make new capacity immediately available. In July 2026, the U.S. Army moved from a one-year to a seven-year PAC-3 procurement arrangement and raised the contract ceiling to $58.62 billion (Ames, 2026). In September 2026, L3Harris Technologies announced that it had received a seven-year contract from Lockheed Martin to supply propulsion systems for PAC-3 MSE interceptors. To support higher propulsion output, L3Harris had begun constructing two new facilities at its Camden site in June, with both expected to become operational in 2027 (L3Harris Technologies, 2026). Until these facilities become operational, new demands continue to place pressure on existing production and stocks. Maintaining selected equipment, skilled workers and qualified suppliers in advance could reduce the preparatory work involved in expanding output when orders increase. Retaining these capabilities entails additional costs, but these may be justified when faster replenishment is needed to meet subsequent commitments.

Ukraine and the Limits of Emergency Expansion

Replenishment capacity depends on the coordination of production stages, rather than the expansion of individual facilities alone. Monthly output of 155 mm artillery shells increased from approximately 14,000 rounds in early 2022 to 36,000 by March 2026. It nevertheless remained below the target of 100,000 rounds per month set for October 2025 (U.S. Department of War Office of Inspector General [DoW OIG], 2026). The same evaluation recorded monthly production of 46,000 metal projectile bodies. However, the facilities responsible for filling them with explosives, completing assembly and preparing them for shipment were still being expanded and could process only 36,000 rounds per month. The constraint therefore lay in the limited throughput of these later stages. Increasing projectile-body production could not deliver an equivalent increase in completed shells without corresponding capacity in other stages of production.

Production readiness also depends on whether manufacturing equipment can produce components that meet the Army’s requirements. At the Mesquite facility in Texas, the contractor had not produced projectile metal parts meeting the standards set out in its contract by March 2026. The Army had accepted a proposal to adapt equipment designed for an older projectile, expecting this approach to be faster than obtaining new equipment. The inspector general linked the resulting difficulties to the adoption of an unproven production process (DoW OIG, 2026). The constraint was therefore not simply the time needed to acquire equipment, but whether the adapted machinery could produce acceptable components. Assessments based solely on completed facilities or purchased equipment may consequently overstate how much ammunition can be delivered within the planned timeframe.

Resuming production after periods of inactivity is contingent on access to essential components and a suitably skilled workforce. The Army’s May 2022 Stinger replacement order was expected to be delivered in 2026, according to the award notice discussed by Nicastro et al. (2024). Although foreign orders had supported intermittent production, some components in the missile’s seeker were no longer commercially available and required redesign. Many workers with the necessary manual assembly skills had also retired (Loidolt, 2025). Fulfilling the new order therefore involved component redesign and the rebuilding of assembly skills, rather than simply raising output. Procurement commitments should make provision for component replacement and workforce training to preserve the technical knowledge needed for future production.

Selective strategic redundancy entails preserving essential industrial capabilities and verifying that the production chain can deliver additional ammunition within the required period. These cases do not show that maintaining additional capacity in advance would have prevented every delay. However, they indicate the need to identify facilities, skills and supplier networks that would be difficult to restore within operational deadlines. Continued government payments for maintaining production readiness should consequently be conditional on contractors meeting agreed output and delivery targets in production tests.

Iran and the Uneven Pace of Missile Replenishment

Replenishment planning needs to distinguish the time taken to fulfil a new order from the time taken to restore depleted inventories. Missiles purchased before a crisis may already be approaching delivery, while additional purchases may not reach stocks until much later. The volume of earlier orders therefore affects how much replacement can occur in the intervening period. A functioning line may support continued deliveries without replacing expended missiles quickly enough to meet the needs of subsequent operations.

Small pre-crisis orders can leave a prolonged gap in replacement deliveries even after procurement increases. In their May 2026 assessment, Cancian and Park (2026) linked recent Tomahawk output of fewer than 200 missiles annually to relatively small earlier orders. The Navy requested 785 missiles for fiscal year (FY) 2027, but deliveries were projected to begin in March 2030. Until those projected arrivals, stock recovery would depend largely on the more limited deliveries generated by previous purchases. Earlier procurement therefore shapes initial stock levels as well as the quantity and timing of subsequent replacement deliveries.

A lengthy manufacturing schedule for new orders does not necessarily imply equally slow stock recovery. Cancian and Park (2026) anticipated a faster recovery for the Joint Air-to-Surface Standoff Missile (JASSM), supported by substantial deliveries from earlier purchases despite heavy use against Iran. For the missiles requested in FY 2027, however, the projected interval between contract award and first delivery was 36 months (Cancian & Park, 2026). The projected recovery of JASSM stocks illustrates how deliveries from earlier contracts can support replenishment before newly ordered missiles arrive. This does not establish that procurement alone explains the different recovery times for Tomahawk and JASSM, since consumption and initial stocks also varied.

Selective strategic redundancy should therefore prioritise munitions whose scheduled deliveries are unlikely to restore the stocks needed for anticipated operations. Long manufacturing lead times alone do not justify additional reserve capacity when earlier contracts already support comparatively rapid stock recovery. Procurement authorities should assess whether maintaining specific production capabilities in advance could provide replacements sooner where existing delivery schedules would leave a prolonged shortfall.

How to Maintain Production Readiness

Selective strategic redundancy could be implemented through production readiness contracts that fund the retention of selected facilities, skills and supply arrangements in return for agreed commitments on additional quantities and delivery deadlines. Existing Defense Logistics Agency (DLA, 2024) provisions include capability assessments and government testing of contractors’ surge commitments. These offer a precedent for adapting existing procurement tools to selected munitions, rather than creating a wholly new contractual instrument.

Funding decisions should begin by comparing anticipated consumption with available stocks and scheduled deliveries. Officials would then assess which industrial capabilities could bring replacements forward sufficiently to reduce the projected shortfall. Procurement authorities should use operational plans and recent munitions consumption to assess demand under several plausible scenarios. These scenarios should reflect different assumptions about how long operations might last and how much ammunition would also be supplied to allies during the same period. Priority should go to capabilities that could reduce shortages across several scenarios and would be difficult to restore within the relevant delivery period. Scenario-based planning would not eliminate the risk of retaining capabilities that future operations might not need. Production tests could verify contractors’ ability to deliver, but not the accuracy of demand forecasts.

Production readiness contracts should separate purchases of munitions from payments for retaining the means to increase output. Minimum sustaining orders would purchase usable weapons while keeping selected production lines in operation and providing continuing work for skilled employees and essential suppliers. Longer purchasing commitments could make demand more predictable, but would not necessarily meet the additional expense of retaining reserve equipment or training workers to support higher output. Separate government payments should cover these specified costs in return for a commitment to increase deliveries when additional orders are placed.

Readiness funding also needs to address constraints throughout the supply chain. Prime contractors should identify critical inputs and formalise delivery arrangements with the suppliers responsible for them. Government financing could support the qualification of alternative sources, with approval from the relevant technical authorities where needed. Stocks of components and materials should concentrate on inputs with long supply lead times and few substitutes, with procedures for replenishing supplies and replacing items no longer suitable for production. For example, DLA’s material-buffer provisions aim to shorten supply lead times by giving contractors access to reserves of critical raw materials (DLA, 2024).

Verification should assess whether contractors can increase deliveries of usable munitions, rather than merely confirm the availability of equipment and facilities. Each readiness contract would specify the additional quantity to be delivered, the maximum time from a new government order to completion of delivery and the period for which the higher production rate could be maintained. Existing surge-testing provisions could be adapted to verify whether contractors can meet these delivery requirements (DLA, 2024). Contractors would also report other orders drawing on the same equipment, personnel or components, allowing officials to check that the promised increase had not already been committed to other customers. The scale and frequency of testing should reflect its cost and the consequences of an undetected shortfall.

Payment schedules should distinguish initial funding for agreed preparatory work from continuing payments conditional on production-test results. Initial funding could be released in stages to finance specified equipment maintenance, workforce training or supplier qualification. Auditable cost records would separate these additional expenses from those already reimbursed through procurement contracts. Failure to meet agreed obligations should trigger corrective action and, under specified contractual conditions, suspension or recovery of payments. At agreed review points, funding could be adjusted or withdrawn to reflect changes in costs, technology and military needs. This would help limit the risk of preserving obsolete systems or subsidising established contractors without a current military justification (Gholz & Sapolsky, 1999). Where qualified alternatives existed, competition for the next readiness contract could be held before the current contract expired, without frequent retendering that undermined longer-term commitments.

Before awarding or renewing readiness contracts, officials should compare retaining reserve capacity with purchasing additional munitions for stockpiling or obtaining further deliveries from allied manufacturers. Larger inventories could cover demand arising before accelerated production could deliver replacements. Procurement from allies could increase supply, but its contribution might be limited if manufacturers relied on the same scarce components. Each option should be assessed against the same projected shortage and delivery deadline, taking account of total cost and reliability. Costs should include both the purchase price of munitions from American or allied manufacturers and the continuing expenditure needed either to preserve the ability to expand production or to store and maintain additional stocks. Readiness contracts should receive funding where the comparison indicates that production supported by these contracts could meet the same demand more reliably, at lower overall cost, or by a deadline that the alternatives could not meet.

Conclusion

Timely replenishment depends on procurement decisions made before a crisis, not simply on the funding available afterwards. The Ukraine case shows how bottlenecks and unproven manufacturing processes can limit deliveries despite investment in additional facilities. Projections following operations against Iran also indicate why assessments of stock recovery need to consider remaining inventories and deliveries from earlier contracts, rather than the lead time for new orders alone. Industrial readiness should therefore be assessed against the quantities needed to restore stocks and the deadlines for delivering them.

Selective strategic redundancy should focus on capabilities whose loss would leave prolonged shortages. Where expected orders would not sustain the necessary facilities, skills and supplier networks, minimum sustaining orders and separate readiness payments could help preserve them. Continued funding should nevertheless depend on demonstrated delivery performance and on how these arrangements compare in cost and reliability with purchasing additional munitions for stockpiling or obtaining supplies from allied manufacturers. Although this approach cannot eliminate uncertainty about future demand or prevent every technical delay, it could reduce avoidable replenishment delays and make delivery commitments more credible before urgent demand arises.

References

Ames, D. (2026). U.S. Army awards replacing a 1-year undefinitized contract action with a 7-year undefinitized contract action. U.S. Army. https://www.army.mil/article/294215/u_s_army_awards_replacing_a_1_year_undefinitized_contract_action_with_a_7_year_undefinitized_contract_action

Army Science Board. (2023). Surge capacity in the defense munitions industrial base. Department of the Army. https://asb.army.mil/Portals/105/Reports/2020s/ASB%20FY%2023%20DMIB%20Report%20%28E%29.pdf

Cancian, M. F., & Park, C. H. (2026). Rebuilding U.S. missile inventory: A multiyear project. Center for Strategic and International Studies. https://www.csis.org/analysis/rebuilding-us-missile-inventory-multiyear-project

Defense Logistics Agency. (2024). Surge and sustainment (Defense Logistics Acquisition Directive, subpart 17.93). https://www.acquisition.gov/dlad/subpart-17.93-%E2%80%93-surge-and-sustainment-ss

Gholz, E., & Sapolsky, H. M. (1999). Restructuring the U.S. defense industry. International Security, 24(3), 5–51. https://doi.org/10.1162/016228899560220

Hellberg, R., Sprängare, D., Candell, O., Carpenfelt, C., Lundberg, K., Samuelsson, P., Antai, I., Andersson, P., & Backlund, L. (2025). Performance constraints in defence industry supply chains: Evidence from case studies. Defence and Peace Economics, 36(8), 1078–1113. https://doi.org/10.1080/10242694.2025.2500362

L3Harris Technologies. (2026). L3Harris receives landmark PAC-3 MSE propulsion contract to power America’s Arsenal of Freedom [Press release]. https://www.l3harris.com/newsroom/press-release/2026/09/l3harris-receives-pac-3-mse-propulsion-arsenal-of-freedom

Loidolt, B. (2025). Ukraine, the U.S. defense industrial base, and the elusive crisis-era munitions production surge. Joint Force Quarterly, (119), 33–46. https://ndupress.ndu.edu/Media/News/News-Article-View/Article/4366531/ukraine-the-us-defense-industrial-base-and-the-elusive-crisis-era-munitions-pro/

Nicastro, L. A., Bowen, A. S., McGarry, B. W., Gettinger, D. M., DiMascio, J., & Arabia, C. L. (2024). Defense production for Ukraine: Background and issues for Congress (Report No. R48182). Congressional Research Service. https://www.congress.gov/crs_external_products/R/PDF/R48182/R48182.1.pdf

Pettit, T. J., Fiksel, J., & Croxton, K. L. (2010). Ensuring supply chain resilience: Development of a conceptual framework. Journal of Business Logistics, 31(1), 1–21. https://doi.org/10.1002/j.2158-1592.2010.tb00125.x

Rogerson, W. P. (1994). Economic incentives and the defense procurement process. Journal of Economic Perspectives, 8(4), 65–90. https://doi.org/10.1257/jep.8.4.65

U.S. Department of War Office of Inspector General. (2026). Evaluation of the DoW’s capability and capacity to produce 155-millimeter artillery ammunition (Report No. DOWIG-2026-095). https://www.oversight.gov/reports/evaluation-dows-capability-and-capacity-produce-155-millimeter-artillery-ammunition

U.S. General Accounting Office. (1996). Ammunition industrial base: Information on DOD’s assessment of requirements (GAO/NSIAD-96-133). https://www.gao.gov/products/nsiad-96-133

U.S. Government Accountability Office. (2005). Defense ammunition: DOD meeting small and medium caliber ammunition needs, but additional actions are necessary (GAO-05-687). https://www.gao.gov/products/gao-05-687

U.S. Government Accountability Office. (2024). Ukraine: Status and challenges of DOD weapon replacement efforts (GAO-24-106649). https://www.gao.gov/products/gao-24-106649