European production is mostly a mixture of a myth to an outright lie. For instance as of late 2024 the commissioner of defense for the EU stated that only 20-25% of EU supplied weapons come from the EU. [1] And similarly EU claims of artillery production were dramatically exaggerated [2]. The EU 'military industrial complex' remains mostly going unsustainably deep into debt to buy US arms. Energy costs alone likely preclude any large scale manufacturing with any degree of efficiency.

[1] - https://kyivindependent.com/eu-to-produce-2-million-artiller...

[2] - https://www.rferl.org/a/ukraine-weapons-shells-european-unio...