So I straight up blew it with my gun the other day. Went for a walk in the mountains in the rain with my shotgun and STUPIDLY put my wet gun into the hard case making the foam wet. Got home and wiped the gun down and put it back in my case to clean the next morning. Problem is the foam was still wet and when I opened the case the next morning the receiver and barrel was covered in rust spots. I had some ultra five wool and sprayed it with ballistol and tried to clean the rust off. Ended up taking most of the rust off as well as the matte black finish 🤦‍♂️🤦‍♂️ All in all a straight up cluster fuck of events.

Anyone know how I can refinish the receiver? Is there a place anyone recommends on Oahu that does this kind of work?

Where was rust? If on outside of receiver and barrel, cerakote. A bunch of guys locally go good work. A few friends have shottys cerakoted.

For removing rust from finished parts, it's best to use a chemical rust remover.

WD40 has a Rust Penetrator formula that works well on surface rust.

I've also used something called Evapo-Rust.  I buy it at Napa Auto stores.  Best to call around and ask if it's in stock, as stores seem to sell out often.  I use it on rusted tools, power tools with steel parts (drill press, bench vise, bench grinder, etc.).

One warning on the Evapo-Rust -- if you leave it applied/soaking too long, it starts to turn the metal a dark color.  Basically, you trade the oxidation for some other chemical reaction that now has to be cleaned off.  A wire brush attachment on a cordless drill works pretty well, but adds work.  Best to just monitor the progress and clean the stuff off once the rust is gone.  The dark stuff might be caused by the rust mixing with the product -- not too sure.  For larger parts, I soak a couple of paper towels in the stuff, place it over the rust, and leave it for a few hours.  Then I check back every hour.  Leaving it overnight is often too long.

Evapo-Rust is a great rust remover, but I'd try it on a spot first, to make sure it's not going to damage the finish, too.

Even after removing the rust chemically, you still want to touch up the spot/s to hide the damage and protect it from rusting again.  They sell firearm finishing and touch-up kits in different colors.  I've looked online, but the places I found won't ship to Hawaii.  I think someone said Young Guns had it once, but never got around to checking.

The WD40 stuff works well, but not as thoroughly as Evapo-Rust.  I'm in the process of cleaning some surface rust off a firearm now with it.  So far, it's doing the job, but taking a couple of days applying with cleaning in between.  No damage to the finish that I can see.

I'd never take anything more abrasive than a toothbrush to a finished firearm surface.

All things being even, I'd say this is a good reason to use something like FrogLube on all your guns.  You can't always control the environment where your gun will be, nor dictate how long it might be in a damp case.  If water gets on it, you need something besides Ballistol to protect it.

There are threads on here and videos and articles comparing firearm rust protection products.  Once you have the finish repaired, you still have to worry about all the pieces and parts that aren't as well finished.

Hawaii = Rust = Sucks.

+1 on the cerakote as he stated above. They will prep it by sand blasting it to ensure everything gets off.

If you wanna be cheap, spray paint it yourself lol. I did for my rem 870. Fuckin when i bought it it already had rustish brown all over. I know its parkerized and the rust brown crap is not touching the actual bare metal but i couldnt live with it. It was bnib, not second hand. I used kroil (some good shit) and alot of rags wiped it all down. Then green brakleen it and had at it.

Hawaii = Rust = Sucks.

I was doing not bad until the 2018 massive vog here in Kona.  I suspect the sulfuric acid from the SO2 vog and heavy water content made an acid bath.  Tools owned for decades with no rust suddenly covered.  Wife says my fault for leaving the garage open too much.

I hear you, it like my wife keeps reminding me, it is ALWAYS my fault.

old timer machinists I know use a bath of Molasses diluted with distilled water. It is supposedly much gentler than commercial acids, but take a LOT longer (weeks) to convert the rust. They prefer that when restoring old mills and lathes to keep the machine tolerances as tight. as possible.