Speaking of 155 mm shells. It seems that production has ramped everywhere.
I recently run on this info about the Spanish ammo factory FMG (Fabrica de Municiones de Granada). Apparently they have its 155 mm ammo line running at 100% capacity (including night shifts) for at least 2023 and 2024. (autotranslated from Spanish)
En clave nacional, la empresa, la única que fabrica en España munición de carro de combate, tiene previsto presentarse al concurso de proyectiles de 120 mm que el Ministerio de Defensa ...
www-infodefensa-com.translate.goog
Actualmente en estas instalaciones se produce munición de artillería, pólvoras de guerra para calibres medios y cargas especiales
www-granadahoy-com.translate.goog
As a curious historical note, FMG is one of the oldest ammo factories in the world. It reportedly had its origin in a powder factory set in the Kingdom of Granada during the XIV century, almost 700 years ago.