Well I took the plunge, went down to Surplus Arms & Ammo and bought a Aero M5 lower. I have never owned a .308 AR let alone built one. I kind of expected it to be like building a AR15 but I can say so far its been nothing like that. So I bought the lower, I plan on using a CMC trigger so I really dont want to buy a entire LPK for the thing since all I really need are the takedown pins and mag release. Aero sells those separate but the long pin is out of stock. I plan on using a Aero upper, I figured at least having those two match would alleviate any worries about compatibility. I was told that the standard DPMS pins will work but the rear is a little short, It does not seem like anyone but Aero sells the Aero pins. I started looking around at BCG and barrels, Which If I can I would like to buy from the same manufacture (that way if there is a headspace issue I know they will take care of it) It seems like BCG vary wildly in price for comparable features. A PSA Nitride BCG is $149 VS a DPMS phosphate @ $289 both made from 9310 I might opt for a Rainer Arms barrel, They are 3 miles from my shop and I hear they will check headspace with one of their barrels free of charge when you buy the barrel. The 18" Black Select is $279 and instock. I hate to buy there BCG though as it is twice what the PSA one is and is made from the same stuff. Aero's Buffer, spring and tube set is not in stock. I am leaning towards using a PWS enhanced buffer tube I have but will still need to source a buffer and spring. A rail seems to be the hardest thing to determine if it will work The Aero says it is a DPMS High (.210) profile. I would like a slim Keymod rail something like the KMR The only one I have found is the Odinworks but they list two options 2.0 and 2.06 and the Aero says 2.10 so I am assuming they will not work, They 15" is out of stock anyway. Anyway now that I have taken the plunge it seems like its a little stressful trying to determine what's what and if all the bits will work together. I am in no real hurry but I would like to get some parts coming to at least get the lower together and start figuring out the rest of the bits. Anyone have some insight or suggestions ?