Available data show that the U.S. has not yet reached 90,000 155mm shells per month, but the prediction’s time horizon (“around 2028”) is still in the future, so it cannot be definitively judged.

Key points:

• A Congressional Research Service report states that U.S. 155mm projectile output rose from about 14,400 per month in 2022 to 40,000 per month by 2024, with a target of 100,000 per month by the end of 2025, not yet achieved as of September 2024. (everycrsreport.com)
• Reporting based on an interview with the head of the U.S. Army’s Program Executive Office for Ammunition and Armaments says that as of June 2025 total U.S. production of complete 155mm rounds was still about 40,000 per month, well below planned milestones (75,000 by April 2025, 100,000 by October 2025). (en.defence-ua.com)
• An August 14, 2025 article in National Defense Magazine quotes an Army spokesperson saying the service is currently producing 40,000 rounds per month and now does not expect to reach 100,000 per month until mid‑2026, meaning even the revised goal precedes 2028 but has not yet been met. (nationaldefensemagazine.org)
• NATO‑related and analytical reporting similarly notes that U.S. manufacturers are at roughly 40,000 rounds per month in 2025, with ambitions of 100,000 per month slipping to 2026, again indicating current output is far under 90,000. (businessinsider.com)

Because:

1. There is no evidence that U.S. production has already reached a sustained ~90,000 shells per month (which would clearly falsify the prediction), and
2. The prediction asserts this level won’t be reached until around 2028, a date still in the future as of November 30, 2025,

we cannot yet say whether Sacks’s timeline is ultimately correct or incorrect. The most we can say is that, so far, reality (40k/month and delayed goals) is compatible with his pessimistic view, but the decisive 2026–2028 period has not arrived, so the prediction remains unresolved.