Do a side by side test on nails.
Great idea, Dave! I've been using FP-10 exclusively on my new gun (Steyr M40), but since I have a very expensive unused bottle of Gun-Guard sitting around calling to me, tempting me to rub some on the slide
, I decided to try your nail test.
The result was that I'm glad I didn't put Gun-Guard on my gun, because the nail I put it on became VERY rusty while the FP-10 nail had only a couple of minor spots.
I did change the test just a little; I added salt to the water, and rather than spray the nails I dipped them in the salt-water once for a few seconds. I did this after leaving the treated nails outside (Florida heat and humidity) for 24 hours with NO rust on either one. (This surprised me.) That's when I moved things along with salt. After that, it was just a matter of a few hours for the rust to start appearing on the Gun-Guard nail. I ended the test about 10 hours after using the salt.
Lessons learned:
1. Wipe down the gun much more frequently than I thought necessary.
2. There's got to be something out there that protects even better than FP-10...and no matter how much money I have to spend, I'll find it...
(This may not be far from the truth, considering the mountain of car cleaning/waxing products I have in the garage.
)