Originally Posted by
Stocky
This happens with lots of modern rifles. I had it happen to a remington 700, browning x, bolt, Tikka and a kimber. It's due to the finish they now do to save money of just sandblasting to get the matter look. I took the same kimber polished it then had it lightly sanded to matte it out again haven't had the issue since and have done a few 8 day soaking wet trips.
I heard from a very reputable gunsmith that he does this to all barrels as the factory just go straight to sandblasting leaving bigger microscopic pits that hold the water making it far more prone to rust. Having done this it seems there's something to it.