NATO has a population 7 times greater and an economy 25 times greater than Russia. There is no reason other than being asleep at the wheel for why nato can't even match Russian shell production
Russia is manufacturing 100k shells a month and are trying to ramp up to 200k a month, so nato should be able to do 200k to 300k easy
Russia is operating on a full wartime economy, NATO countries aren't. In addition to which Russia is exchanging oil and gas at undervalue with Iran for arms