Hello everybody. Brand new user here. This is actually my very first thread-post ever. So please don't judge too hard in regards to my "thread-etiquette" lol X ) But ok... Here it goes: Imagine a "Walking Dead-type," zombie apocalypse, scenario... Having to fight in CQB-type situations, indoors; decent distances, outdoors; low temperatures in the snow; warmer temperatures around 95; etc... AR parts may be scarce... How would you guys build an AR for ultimate versatility & longevity? (Obviously while still being ultimately reliable.) I realize I could've just said something like a "civil unrest scenario," but I like my proposed scenario better =D lol. 1) Versatility - You would want your AR to always be of use - you wouldn't want your AR to be too far on one side of the spectrum (too much of a CQB build, or too much of a long-range build). & you would want to use just about any ammo you find. I just recently heard about "Reece builds" it seems like versatility is the purpose of that type of build, yes? 2) Longevity - You'd want your AR to be setup in a way that has the least amount of wear & tear on important parts (barrel, BCG, etc...), able to last as long as possible. So, with these priorities in mind, what're you guys thinking? - 1:8 twist for use of most common rounds (55gr), along with heavier rounds if desired? (Versatility) - Chrome-lined CMV barrel, instead of Stainless Steel. (Longevity) - 16" barrel with mid-length gas system? (16" - not too long & not too short) & (mid-length for lower bolt velocity?) Would that be a good setup in regards to dwell time & BCG velocity/longevity? Or maybe 14.5" with carbine system? Would that be better for dwell time & BCG velocity? Would a 14.5" barrel not produce enough "umph" past a reasonable distance to put somebody down? Would 14.5" barrel be too short for 1:8 twist? I apologize if I typed this out in a confusing way. I've been getting interrupted all day as I've been typing this; & I just want to get it over with now lol. & I thank everybody in advance for your replies.