A fox shooter brought this in recently.its a tikka 595 factory barrel which has had the sound moderator left on for around 3years and never been cleaned.he didn't no how many rounds he put down the barrel exactly.he said hundreds.the sound moderator was a Reflex.the internal sleeve had corroded away causing all the pitting and fouling on the barrel exterior.the bore is completely shot as one would expect.i see quite alot of crown damage where the moderator is left on.usually a inch or two removed recut thread and crown does the trick.this one had to have a new barrel.