The 155mm shell decides wars of attrition. Since 2022 the calibre has moved from a quiet procurement backwater to the loudest capacity race in the Western defence industrial base, and ISC has tracked it contract by contract. This hub gathers every ISC briefing on 155mm ammunition: new production plants and joint ventures, propellant and energetics constraints, extended-range projectile programmes, framework awards through NSPA (the NATO Support and Procurement Agency) and national agencies, and the interchangeability questions that follow when a dozen nations buy the same calibre from different lines. Coverage is open source, dated, and scored to NATO STANAG 2022 standards.