Been shooting corrosive Yugo M67 thru an AR for 4 or 5 years now, no corrosion and I flush thoroughly with hot water to remove salts before cleaning. Til recently I'd just flush the upper & BCG. Although I've never had any corrosion issues, when I picked up my second 7.62x39 AR I also started flushing the lower, removing the buffer & spring and flushing the tube and my stainless steel mags as well. Since we're talking corrosive salts either it needs to be cleaned immediately or not, can't wait and just give it an annual cleaning like non-corrosive. It's only another 5 minutes of cleaning.

If your time is worth more than the parts you would need to replace you can cut back and see if you are overdoing it.

I only done black powder and always got rust no matter what I did to clean it.

Get  yourself some Ballistol.  Read the label, and then clean AND lubricate with it.

Been using the Ballistol for a while now. Great stuff for corrosive, and since it's water soluble it rinses right out with a flush and takes more of the carbon with it than a product like Breakfree CLP.

And I found my answer, opened up some of my ASC 20 round magazines last night to check for rough spots and found the springs has some surface rust. Never had this problem with the ASC 30s but these new 20s use a flat wound spring so must be different material.  So I'll just keep doing what i'm doing.

Ballistol goes into emulsion with water when it is fresh. It is meant to be added to water to form the emulsion which would then be used to wash the gun to neutralize the salts. Then you can let it dry and follow up with straight Ballistol. Spraying Ballistol on then rinsing it off with hot water is not bad but not as good as doing it right. Either way you come back after it dries and use Ballistol as your CLP. I find that it is the most satisfying oil to use on an AK. I've never tried it on an AR, where I tend to like Hornady 'One-Shot', but then again, I would never shoot corrosive in a 7.62X39 AR either.

I just finished up a 880 round case of corrosive Czech 7.62x51 through my GII MOE. Sprayed the BCG, barrel, and upper receiver down with a 50/50 Ballistol water mix after each range trip. Followed up with straight Ballistol for the final cleaning. For the gas tube I use a short  piece of clear nylon tubing slipped over the end and pump Ballistol water mix through the tube.