It's the only Primary Secondary in the game, it's a shotgun.. but it's a Primary. It's very rare to find, only in heroic nightfalls or a very very low chance (1%) in the crucible. It's OP to be honest, because with the "universal remote" perk you can aim down the barrel and get a instant kill headshot from 200ft (greatly increases range and precision damage while aiming down the barrel). Plus it never runs out of ammo being a primary..