How Versailles removed Germany's heavy-gun production base

Why could Germany not arm Scharnhorst and Gneisenau with 15-inch guns from the start?

Versailles had stripped away the relevant heavy-gun production capacity, so Germany built available 11-inch weapons while developing a new 15-inch system.

Germany did not choose 11-inch guns for Scharnhorst and Gneisenau simply because that caliber best met naval requirements. The Treaty of Versailles had removed the facilities and inherited production path needed for modern 15-inch weapons. British 15-inch Mark I guns used wire-wound construction, while the newer British and German heavy-gun programs required different solid-built designs and tooling. Germany therefore fielded the caliber it could manufacture while developing a separate 15-inch system, illustrating how arms-control settlements shape industrial options long after signature.