The 155mm Ammunition Capex Boom: Rheinmetall, Nammo, CSG and General Dynamics

Why 155mm Became the Bottleneck

The war in Ukraine has been, above all, an artillery war. At its most intense, daily expenditure of 155mm and Soviet-calibre rounds ran into the thousands on each side. Western armies, optimised after the Cold War for expeditionary precision rather than mass fires, had no production base to match that tempo. Annual peacetime output of 155mm shells across the entire NATO alliance was a small fraction of what Ukraine could fire in a few weeks of heavy fighting.

The result was rapid stockpile depletion. Donor nations drained their war reserves to keep Ukraine supplied, then discovered that refilling those reserves required production capacity that had been allowed to wither. The shell itself is only the visible part of the problem: each round depends on forged steel bodies, explosive fill such as TNT, and nitrocellulose-based propellant, and every one of those inputs had its own thin, neglected supply chain.

Because energetic-materials plants and forging lines take years to design, build and certify, 155mm output could not simply be switched on. That structural lag is exactly why ammunition became the defining bottleneck of the war and the magnet for the capex described below.

The Capex Wave: Who Is Building What

Rheinmetall has led the European response. The German group says it is targeting up to roughly 1.5 million 155mm rounds a year by 2027 across its sites, a scale unimaginable before the war. Its centrepiece is the new Unterlüss plant in Lower Saxony – the company’s “Werk Niedersachsen” – opened in 2025 and described as Europe’s largest shell factory. Rheinmetall expects it to ramp from about 25,000 rounds in 2025 toward roughly 140,000 in 2026 and up to about 350,000 a year by 2027.

In the Nordics, Nammo – jointly owned by the Norwegian state and Finland’s Patria – is expanding artillery-ammunition and rocket-motor capacity. The Norwegian government has backed national ammunition production with support reported at around NOK 1.95 billion. Because Nammo is a major European source of propellant and rocket motors, not just finished shells, its expansion relieves an upstream choke point that constrains everyone else.

Central Europe’s standout is Czechoslovak Group (CSG), a Czech conglomerate and major producer of artillery ammunition and large-calibre rounds. Its revenue jumped from roughly €0.6 billion in 2021 to about €4 billion in 2024, and in January 2026 it listed on Euronext Amsterdam at a reported market value of around €33 billion – a vivid measure of how valuable shell-making has become. Across the Atlantic, General Dynamics, through its ordnance and tactical-systems arm, is expanding US 155mm production as the US Army rebuilds its artillery industrial base.

Producers and Capacity Targets

The table summarises the main producers driving the 155mm capex boom and their approximate capacity targets or growth, with as-of context. All figures are rounded company targets or reported estimates, not delivered volumes, and several depend on upstream propellant and explosives supply being available in time.

⚠ Figures are approximate, rounded company targets or reported estimates as of their source dates (Rheinmetall, National Defense (Nammo), OSW (CSG), General Dynamics). Targets are not delivered volumes. Not investment advice.

EU and US Output Targets

The headline producer targets sit inside larger political goals. Since 2023 the European Union has pressed member-state industry to lift combined 155mm production sharply, citing ambitions in the region of two million rounds a year by 2026. That figure is an aggregate of many national producers – Rheinmetall, Nammo, CSG, Nexter/KNDS, BAE Systems and others – rather than any single plant, and it has slipped against the original schedule as upstream supply lagged.

The United States set its own benchmark: lifting 155mm output toward roughly 100,000 shells a month, a multiple of pre-war rates. General Dynamics’ ordnance business and government-owned, contractor-operated plants are central to that effort, alongside new metal-parts and load-assemble-pack facilities. The US programme has emphasised modernising ageing army ammunition plants as much as building greenfield capacity.

Both targets are best read as direction of travel rather than guaranteed delivery. Capacity on paper has consistently arrived faster than the energetic materials needed to fill it, so reported output has trailed announced capability throughout the ramp.

Execution Caveats and Risks

The biggest constraint is upstream of the shell. TNT and other explosive fills, nitrocellulose propellant and the machine tools to make them are all in tight supply, and qualifying a new explosives plant can take several years. A finished-shell line can be commissioned faster than the energetic-materials capacity that feeds it, which is why headline numbers routinely run ahead of delivered rounds.

Ramp-up time is the second caveat. From decision to meaningful output is typically two to four years for a shell line and longer for explosives, and full rate arrives in steps, as Rheinmetall’s Unterlüss schedule shows. Skilled labour, long lead times for forging presses, and the need to certify every new energetic batch all stretch the timeline.

The third risk is commercial. Much of this capex is underwritten by wartime consumption and the need to refill depleted NATO stockpiles. A durable ceasefire could slow new orders and leave the most aggressive expansions under-utilised. Against that, refilling reserves is a multi-year task and framework contracts are signed in advance, so a sharp reversal of capex is not the base case – but it is a genuine downside that investors and planners weigh. This page takes no view; it is analysis, not advice.