I can't find fault with Blue Wonder, it's by far the easiest and quickest. A major plus is that you can easily touch up worn bluing, there no need to refinish the entire gun to get a good result............ It's nothing like a traditional blue, it's something completely different.
The barrel bands and butt plate below are painted with high temp engine paint then baked for 2 hours at 300 degrees. Everything else has been touched up with blue wonder in about an hour.
PS, Heat needs to be applied with a blow torch when using the blue wonder