tl;dr; - The US has government-owned (but contractor-operated) munitions plants, and boosting production is an actual (vs. lip-service) priority. The EU has a bunch of purely-private producers, all hog-tied with regulatory and financial constraints.

Cynical suggestion: An annual EU-wide "which country can boost production the most?" contest. Leading politicians from the losing countries are rewarded with six months in the front lines in Ukraine.

or US see a business while Europe see a cost. it's how business work: if you produce and consume your product, you at best earn nothing.

I also think US are a single entity while EU is multiple, US have traditionally a bigger defense industry...

Goodhart's Law will have a field day with your suggestion :)

A Euro-munition contest?

meanwhile in reality:

https://bulgarianmilitary.com/amp/2023/10/21/russian-army-ha...

shell condition is definitely a big "if" there, the shells are inconsistently packed and apparently factory workers will steal the (hard) copper forcing wire that cleans the barrel from fouling from some of the shells... and powder that is not stored consistently is itself dangerous and unpredictable. heat, humidity, time, etc all can paradoxically increase the burn rate of powder grains, stabilizing agents leak out etc.

https://en.wikipedia.org/wiki/1967_USS_Forrestal_fire

there's an insane amount of 8mm mauser out there due to it being a relevant caliber for like 60+ years, and some of it has been stored in awful conditions and tends to... develop overpressure.

https://www.youtube.com/watch?v=AunvMjcJPHY

Aren't NK shells notoriously unreliable and have large rates of duds?