[fso301]

Howitzers, for example, are having their barrel rifling wiped out.

I would expect the barrels are only good for about 500 rounds tops.

[skepsel]

More like 2,500 rounds, not 500.
At that point the tube can be relined and rebored, restoring the rifling.

This means disassembling the gun and returning the tube to the foundry.

Not a simple process.