I was just checking out a website looking for a spare bolt and found a bolt that is Nickle Boron coated. There are claims of high lubricity and cooler operating temps.
Is NB for real or are there some downsides I should be aware of? I'm just looking for a spare that will probably never get used, since I'm a plinker who will take a few classes whenever time and money allow it.

Thanks all,
Oak