I was eager to try it until I saw that it is made by the same people that made FP10. I got a free sample of FP10 and bought four Allen wrenches and grinded them down to bare metal. I cleaned them and left one unprotected and applied break free, corrosion x and FP10 to the other three. I placed them outside and the unprotected and the FP10 had rust on them the next day the other two took several weeks to start rusting. I repeated this several time mixing up wrenches and got the same results. But I will give this a try too.
You probably used the newer formulation of FP-10, which is no longer owned by Fennell. I have the older formulation of FP-10 and ran corrosion tests with it and many other products years ago (2002 or 3...I forget). Well it was superior to all others, being rivaled admirably by only Eezox and Corrosion X. It blew away the old formulation of Breakfree.
Interestingly, a few years later before I knew that Fennell no longer was a part of FP-10, I came across a post where someone ran a corrosion test with FP-10 (newer formulation) and had the same results as you. I replied with my own experience and neither of us could figure out why we got different results. It wasn't until later still when I ran across an announcement by Fennell that he had parted ways with the Firepower company he helped started, some time before and they had changed the formulation. Fennell had then begun the Weapons Shield line separately. It all made sense after that.
Unfortunately (or fortunately), I just am not too sure I should buy any of the new stuff when I stock-piled so much of the old FP-10!...which is awesome, by the way. But if the new Weapons Shield is really that much more superior compared to the original FP-10, then maybe I may have to.