Let me do the math another way. How many of those howitzers do you think we have shipped to ukraine? I will take a completely random guess at 155 of them. A number I have no more idea if that is true then the man in the moon. Do those howitzers have a 1,000 round Barrel life?
Have no idea what the barrel life is of a M777, even less of an idea on SPGs like the Krabs, Caesars, Phz-2000s or Zuzanas. Longer than the Soviet era artillery likely, which is what the Orcs are using except for half dozen modernized pieces.
Although I think there was a complaint that the German 2000s wore out after 1000 firings or so and became useless until fixed.
“Do those howitzers have a 1,000 round Barrel life?”
2,500, is more typical, then it gets inspected, and extended a few hundred rounds more between inspections, until it fails inspection (maybe 4,000).