Ok so very very new to AR's and recently purchased my first, I got a DPMS AP4 .308! That only started the fire now I got 3 CMMG lowers on order so I can do some builds to learn more about the gun as I piece them together. My main question is what all does it take to build a full ready to fire rifle. I'm not talking about all the extras you can toss on, just the basics to get the rifle to fire a cartridge. Obviously so far I know the lower, then I'm gonna need a lower parts kit. A butt stock (not really part of the firing aspect but a must for the rifle) And then an upper. Thats all I can think of with those combined the rifle should fire correct? Then from there yes I can add optics, rails, lights and all kinds of fancy stuff. So are my at least on the right track?