I got one from a nightfall with Persistence, Field Scout, Lightweight, Hammer Forged, and Rangefinder. Overall, I think I might have one of the best possible rolls, because it has sheer all-around usefulness. It can be equivalent to a scout rifle, it can make me a little faster, it can have a 42 round magazine versus a 22 round magazine, AND it gets more accurate the longer I shoot. Overall, the only thing that would be better would possibly be a damage buff/reload speed buff perk. Too bad I'd have to sacrifice either Rangefinder or Persistence for that, though, so I'm happy with my random nightfall reward.