Lyrically, the song, along with its respective album, are related to the band still being together and functioning well as an unit for over twenty years Frontman Sully Erna said of writing the song:

I always write about things that have affected me on an emotional level...But if I choose to do that, I have to be prepared to be honest and vulnerable. And so the challenge is figuring out how 'exposed' you want to be with personal information. But I've also learnt over the years that, for me, being transparent, even to the point of embarrassment sometimes, is so much better than holding it inside and extending that pain longer than you need to. 'Bulletproof' is just another moment in my life when I allowed myself to be vulnerable and got hurt. It's this kind of carelessness from other people that eventually hardens you and forces you to put up that wall to protect yourself. So when and if they circle back around and try to get back in, you make yourself bulletproof.
-from wikipedia

Regular here if I have time, not regular if have no time and going somewhere like out of the city, state, or foreign land.

A traveller