Ice breaker is exotic level. It's ability to have endless ammo makes it an exotic and the time it takes for the ammo to regenerate is to make it not over powered. Black hammer is a legendary so shouldn't be able to compete with ice breaker but it does. It has infinite ammo with no need too stop firing at all as long as you chain precision hits, which on most bosses isn't hard at all. It will still be a godly gun, like 18 shots without having to reload is still pretty amazing, and then it's just a case of picking up a couple special ammo and your good to go again, the nerf isn't really that bad...