AS UKRAINE COMES under mounting pressure on the battlefield, Europe is desperately  scrambling to boost its puny production of artillery shells and missiles. In January the EU admitted that it had fallen well short of its pledge to provide Ukraine with one million shells by March 2024. On March 15th it allocated €500m ($542m) to ramp up production. But the biggest bottleneck is something that was an afterthought until recently: a shortage of explosives.

The scheme in question  is called the Act in Support of Ammunition Production (ASAP), and three-quarters of the funding, or some €372m, will be lavished on manufacturers of things that go boom. Europe needs bushels of combustibles to reach its target of producing 2m shells a year by the end of 2025. Each artillery shell is crammed with 10.8kg of a high-explosive such as TNT, HMX or RDX. Additional propellant charges are also needed to hurl the rounds over tens of kilometres. Other munitions require even larger amounts: the high-explosive warhead on a Storm Shadow missile, for example, weighs around 450kg. The trouble is that explosive makers are unsure that production can be cranked up and fear that the quirks of the industry will hamper the surge that Ukraine needs to remain competitive on the battlefield.