I The steel only rusts where the rusting chemical is applied. Now I just degrease the bore and start bluing. When the barrel is removed from the boil, the steel drys instantly. After carding, I run a clean patch through the bore using a degreased rod to remove any crud .
My bluing jobs usually take a couple of days and I've never had a problem with barrel rust.
I believe you, but find it really interesting, as I have had rifles start to rust after being out in rain a couple of hours.
