I took the plunge and did a naval jelly job on an entire barrel assembly. I have always been hesitant as I didn't want to get splotchy areas, and wasn't confident it would work period.
I got this BCM 11.5" barrel with perm attached faux moderator at the local show this past weekend. It is new, and it was only $160. I posted another thread about my scores from the weekend. I thought the color looked kinda grey, but it turned out to be pretty black.
It was an almost black color, not quite black, but not acceptable for my GAU-5/A/A build. So, I thought I'd at least try the naval jelly trick on the barrel extension, as it won't be visible once installed, just in case it didn't work out. Well, it worked out. Pretty nice actually.
Here's the particular product I have been using for the retro grey look, with excellent results. I typically use a toothbrush to apply it, gets it in the cracks real good.
Once I got the courage up, I went ahead and coated the rear half of the barrel, from the handguard retainer back.
Only had to leave it on for about a minute, maybe two. Once that part cleaned off good, I went ahead and did the FSB and barrel up to the "grenade ring". Cleaned it up and it looked pretty good and grey. Going good so far. You can see the contrast between the moderator and the rest of the barrel assy.
After that, I went ahead and did the moderator.
Got her all cleaned up and was very pleased with the initial results.
Upon a good drying period, and further inspection, I could tell that she was REALLY dry, and needed something.
So I gave her a nice bath in some of the best grease on the planet....
After a good wipe down, she is looking pretty damn good! No splotches, streaks, or unevenness. Couldn't be happier!!
Here she is next to my 653 barrel, you can see how grey she turned out. Maybe a little lighter than an original, but it will be perfect for the build I'm doing. It's going on a light grey upper and lower worn through to gold (havent done those yet), so I think it will complement them nicely.
All in all it went pretty well. YMMV.