The Propellant Shortage: Why Gunpowder, Not Shells, Is the Bottleneck

The Binding Constraint

In any production chain, output is governed by the slowest link. For 155mm artillery, that link turned out to be propellant. A shell becomes a usable round only when a steel body, an explosive fill, a fuze and a propelling charge of gun powder all come together — and of those four, the powder was the hardest to scale.

The reason is industrial. Forging and machining steel shell bodies draws on capacity that exists across the wider metals sector, so it expanded comparatively quickly after 2022. Manufacturing energetic nitrocellulose and propellant is a different proposition: a hazardous, tightly regulated chemical process concentrated in a handful of specialised plants, with little spare capacity built in during the long peacetime lull.

The result was a recurring frustration for Western planners. They could announce large shell-body and assembly capacity, but the number of complete rounds that could actually be fired tracked the powder supply. Propellant, not steel, set the ceiling — and it is the central reason the EU's two-million target and the US Army's 100,000-a-month goal both proved harder to reach than the headlines implied.

Feedstock: Cotton and Wood Pulp

Propellant begins with nitrocellulose, or guncotton, made by treating cellulose with concentrated nitric and sulphuric acid. The cellulose comes from cotton linters — the short fibres left on cotton seeds — or from purified wood pulp. The choice and quality of feedstock affects the powder's properties, and the supply of suitable cellulose and acid is itself a potential constraint.

This feedstock dependency adds a layer of fragility beneath the already-narrow propellant industry. A defense base that relies on specific cellulose grades and a limited set of nitration plants has multiple places where a disruption — an accident, a feedstock squeeze, a regulatory shutdown — can throttle the whole chain. It is the deepest, least visible tier of the artillery supply chain, and the one with the least redundancy.

That is why the post-2022 effort reached all the way down to nitrocellulose itself, not just finished powder, with companies racing to secure their own guncotton supply rather than depend on third parties.

Single Points of Failure

The fragility was not theoretical. In August 2022, an accident shut down nitrocellulose production at Eurenco's Bergerac site in France — one of Europe's key sources — and the line stayed offline for months while damaged equipment was removed and the facility restored and re-permitted. A single incident at a single plant had removed a meaningful slice of European nitrocellulose capacity overnight.

That episode crystallised the single-point-of-failure problem. With so few plants, there was no easy way to route around a loss. The same logic applied across the chemical base: one RDX line at Holston in the US, a thin set of nitrocellulose producers in Europe, limited acid and feedstock suppliers behind them.

Recognising this, Rheinmetall moved to internalise supply, buying the German nitrocellulose maker Hagedorn-NC. CEO Armin Papperger framed the deal explicitly as closing "a strategic bottleneck in propellant production" — an unusually candid acknowledgment that the powder tier, not the shell, was the problem.

The New Powder Plants

The European response centred on a cluster of expansions. Eurenco, having restarted Bergerac, committed roughly €500 million to lift powder production around tenfold and double modular-charge capacity, targeting about 1,200 tonnes of explosive powder a year — equivalent to roughly 500,000 modular propellant charges — chiefly for 155mm artillery, with workforce at the site growing toward 450.

Rheinmetall and RUAG expanded their Nitrochemie joint venture in Wimmis, Switzerland, and in Germany, with Swiss lawmakers backing the capacity increase. Across Europe, reporting described an initiated expansion of gunpowder capacity on the order of 10,000 tonnes a year. These additions underpin the European drive toward roughly two million 155mm shells annually, but they arrive in stages over several years rather than at once.

The detail on individual makers — Eurenco, Nitrochemie, Chemring Nobel and others — is covered on the explosives makers page; here the point is the aggregate: Europe is rebuilding its powder base from a dangerously thin starting point.

The US Side

The United States faces the same arithmetic. The Army's goal of around 100,000 complete 155mm rounds a month is not just a metal-parts and load-assemble-pack challenge; it depends on enough propellant and energetic material to fill and fire those rounds. Officials have repeatedly flagged propellant and explosives production as a constraint requiring further investment, even as monthly output rose from about 14,500 shells before 2022 to roughly 40,000 in 2025.

That is why the US ramp pairs new metal-parts and assembly lines — such as the Mesquite, Texas site — with efforts to rebuild domestic explosives and propellant capacity, including new TNT production. Without the chemical tier, the metal tier simply produces empty bodies.

The strategic conclusion mirrors Europe's: scaling artillery output is fundamentally a chemicals problem, and propellant is its hardest part.

Capacity at a Glance

⚠ Figures are approximate and from Defense News, the European Commission, SWI swissinfo and company statements from Eurenco and Rheinmetall. Expansion numbers change as projects progress; verify the as-of date.