Originally Posted by Seraph
That nickel boron coating should be unable to rust, and the Tenifer treated steel underneath should be really damned resistant. Given those two factors, it seems more likely that something else has gotten onto, or into, the finish on that pistol, and has rusted. Some kind of contaminant got in there during finishing. No doubt they'll refinish without argument.
This, an EXO finish isn't typically going to do this. This gun needs to be refinished. I prefer the standard glossy finish of a Glock, but wouldn't feel like I had a non-durable gun with the EXO finish.