Put the upper together yourself. Buy a good Type 2 barrel and a headspaced bolt or BCG. Companies like Sons Of Liberty Gun Works offer a 16” 6.5G barrel, and will match a BCG or bolt to it for you. That’s a rock solid barrel that’s a proven performer, with a top notch BCG.
Companies like Ballistic Advantage and Odin Works also offer a barrel/BCG combo, although I’m not a fan of nitrided BCG’s, which they both come with. Most folks don’t have an issue with them.
Any standard AR15-type upper should work on your DB AR15 lower.
Yeah I started looking through the Firearms chat and realized I was not going to go BCA. I read an article on pew pew and they tested 5 complete uppers and I like the Sanders and it comes with complete upper with the Type 2 barrel for $468. They shot a .57 MOA at 100 and a 1.56 MOA at 400 yards. The only downside I see is it comes with Nitride BCG. What is an issue with Nitride BCG?
https://www.pewpewtactical.com/best-6-5-grendel-uppers/
cheap and good goes well together doesn't it 

