Were these your first builds?
Yeah, something I've been intending to do for a very long time. I started gathering parts like the week of sandy hook, so got pretty lucky on my timing and have not had to overpay for anything. My lowers are identical: Essential Arms stripped lower, DD lpk, Magpul BAD levers, Magpul UBR stocks. The 300 blk is the AAC 16" complete upper, the 5.56 is 16" BCM. Both have Magpul flip up sights, but the blackout also has an Aimpoint PRO. The assembly and firing of them has been very enjoyable.