Rheinmetall intends to increase their annual production to 750k by 2025 and the US is aiming for 1 million annually by 2025. That's still much less than Russia and that's before considering they have access to the significant reserves and the factories in North Korea.
> Since August, Pyongyang has shipped about 6,700 containers to Russia, which could accommodate more than 3 million rounds of artillery shells or more than 500,000 rounds for multiple rocket launchers, according to the South Korean Defense Ministry.
https://news.sky.com/story/russia-is-producing-artillery-she...
https://edition.cnn.com/2024/03/07/asia/north-korea-artiller...
https://www.rheinmetall.com/en/media/news-watch/news/2024/02...
https://www.army.mil/article/274905/munitions_for_ukraine_ob...