I understand that SS to easier to machine well, so it is theoretically easier to make an accurate SS barrel. As far as 16" vs 18", if the goal of the rifle is target shooting on a flat range at longer distances, I still like my 18" barrel for the added velocity. If I wasn't shooting past 400, I'd probably do a 16". That being said, I've made hits to 800 with my 16" w/69gr TMKs and my 18" w/77gr TMKs.