Fatebringer. Firefly, practically the same as what Icebreaker does.

Exploding rounds tends to mess with the firefly and outlaw perks. Single point sling doesn't do much for me as I tend to mostly run primary. And field scout adds only one round to the mag while carrying extra in reserve that don't really matter because primary ammo drops like it's nobodys business. Firefly also exists outside of Fatebringer while White Nail is a Black Hammer exclusive. I could run a scout with firefly and similar perks and it would be just as good with increased range. The only real comparison to Black Hammer is Bad Juju. I don't feel as though a legendary should be comparable with an exotic.

No one I know uses explosive rounds on fatebringer. They aren't necessary.

That doesn't answer the fact that technically Fatebringer isn't OP. The only thing that really helps it is having an element. If it didn't, there's no way it would be as coveted as it is.

You're delusional if you think Fatebringer isn't one of the most powerful weapons in the game. Many people, myself included, would take it over any of the primary exotics any day of the week.