I am looking to make my way into the Class 3 world and I can't decide what to do. I am hoping someone can give me some advice. My dilemma is, should I use the sig m400 that I already have and just change out the barrel and gas block, giving me exactly what I want, or build a new rifle? I have a line on a Yankee hill lower. I am leaning towards saving a thousand and using the sig I already have but is it a mistake to go with a sig over a Yankee hill? The upside to the sig is that it's a good quality rifle and everything works flawlessly and should still changing only the barrel and gas block. That and I can have an sbr for about $500 (with the stamp and engraving) vs the $1500+ to build one.