It doesn't, although for most purposes the semi-auto sniper rifles work in the exact same capacity. They do enough damage that the shots to kill won't change against targets with Nanoweave upgrades, while the Nyx goes from 3 to 4 with even a single rank. I believe that the projectile velocity and damage loss over distance are far worse on the Nyx as well, but I haven't tested that so you'll probably want someone else's opinion.
wont get far shots too well, but no. no sway (imo all guns besides fixed weapons should have sway) also, the hs/nv scope is the best for it, hardly ever need it at ranges that will exceed the scope