Euronews fact checked the statement and found that ammunition production may have been approximately four times more than that of the NATO Alliance in 2024. On paper, NATO’s economy is 25 times bigger than Russia’s once again illustrating that GDP measure doesn't tell you much of anything about the real economy.
https://www.euronews.com/my-europe/2025/07/16/is-russia-producing-a-years-worth-of-nato-ammunition-in-three-months
Ok, but Russia currently has a "war economy" so ammunition is going to be a key production area.
By contrast Nato members are having peace time economies, where ammunition is less of a need.