[GLOOB]

I used some Casey's selenium cold bluing solution on my pistol, where I had done some grinding/polishing. I found it ridiculously quick and easy, and I didn't strictly wash the parts aferwards in water... is that a big oopsy?

Anyway, the real question I'm wondering about is: why should you not blue the inside of the barrel? I blued the crown, and instinctively stopped there, which I'm glad. Then I googled and found you should definitely NOT blue the inside of the barrel, but I haven't found out why. I am guessing it increases the friction?

[patrolman]

never blued the inside of a barrel, but I suspect that it would probably be wasted effort. I doubt the bluing inside the barrel would last past the first few rounds fired through it. also, as I understand, any bluing is a "rusting" process. i would be leery of deliberately introducing rust of any kind into the inside of a barrel... but I'm no expert.

[dfariswheel]

Bluing has no effect on the bore one way or another, AS LONG as it's rinsed and oiled properly.
Some re-finishers plug the bore and some don't.

You MUST plug the bore when using parkerizing since it's an actual build up on the metal.