Rounds.

This is coolbert:

 Expenditure of ammunition the Ukraine Conflict by both side prodigious to say the least.

From antiempire.substack.com

"So Much for Counter-Battery Fire: Ukrainian Howitzers Are Surviving to Have Their Barrels Wear Out"

"RU [Russian]arty has underperformed expectations but maybe we're to blame for having them"

"The artillery the West has provided Ukraine is 'breaking' the NYT says"

[....]

BREAKING BUT NOT BECAUSE OF INFERIOR DESIGN, MANUFACTURING, MATERIALS.

"A barrel wears itself out over time. That’s a normal thing. But that Ukrainian howitzers are living long enough for their barrels to wear out tells us that they’re mostly not being taken out by Russian counter-battery fire."

"By late October Ukraine had received 1.1 million 155 mm shells. The majority of these have been expended, fired by just 350 155-mm weapons in Ukrainian hands. That Ukraine successfully fired off around a million shells is another indication Ukrainian artillery isn’t being suppressed."

That is about 3,000 rounds fired by each unit of tube artillery. Equipment just "breaking down" from excessive usage, wear and tear. I might imagine that includes ALL NATO artillery of the 155-mm caliber. 

Consider too ammunition expended within context of the Battle of Verdun, 1916, the Great War:

"Millions of shells were fired in single battles, with one million shells alone fired by the Germans at the French Army in the first day at the 1916 battle of Verdun"

coolbert.