Hi Doug, thanks for your reply. I guess the fault with my idea or question lies within this part of your answer:
"... so by merely boiling some years later, no further color changes will take place after the oxide layers have been stabilized."
I was not considering whatever chemical change that may be occurring during the stabilizing or curing phase. But I do know that the oxide is not so strongly adhering to the barrels for a while immediately after finishing. In fact, I've noticed that some products like WD-40, which is supposedly not a penetrating type oil, will remove a portion of the fresh browning or bluing if used too soon after a refinish. But a year later, the same WD-40 can be used with 0000 steel wool to remove a rust speck, and with light rubbing, it won't hurt the bluing at all.
Now I'm curious what actually is going on chemically. The plot thickens.
