So I have a barrel that was re-profiled. Heavy to pencil. I did a cheap re-bluing in a bottle.

I took the upper apart to swap hand guards and noticed the cheap bluing is not holding up too well.

Is there any problem in ceramic painting the barrel. I have some super high heat paints, like engine enamel and header paint for cars.

I have read that the ceramic paint might keep heat in, but is it really an issue on a semi auto gun that gets shot a lot but not sure how much heat I would be building up.

Just get some RustOleum dark gray auto primer

I have a 16" and a 870 barrel painted with Rustoleum camo paint and has held up great for years now

And what did that cost you $20?
Why would anyone pay more for a paint and then more to have it removed is beyond me.

And then repeat the above.  I don't get it

What exactly is your question?

I had a barrel and got it re-profiled, I happen to live locally to ar15barrels.com and he does fantastic work. So it was cheaper for me to get a barrel down the exact way I wanted in front of my eyes.

After, the barrel is bare steel. I got some $7 bluing stuff at the local gun shop. But it is not holding up very well as there is surface rust developing in some spots.

So I asked about High temp spray paint

Meh, I paid somewhere around $200 for a Patriot Brown job on an AR receiver set and barrel last year. It seemed like a good idea at the time. Then I moved to a green state and the brown just stopped appealing.

Now I'm going to pay more to have it blasted back to bare metal, but I can't seem to find a vendor willing to blast it and return it to me (as I plan on doing my own refinish using Norrell's)

It's only money, you can't take it with you.

Still don't get it.

I don't throw money around like the city hall