I am going to be putting together a 6.8 AR soon. This will be my first build project and i have a few questions. Do I need to get a specific upper made for 6.8? is there a specific bolt for it? Where is the best place to get barrels? I was wanting to do a flat top with flip up rear and front. I like this upper http://www.del-ton.com/MidLength_VIS_with_Bolt_Assist_and_Shell_Deflector_p/ur1025.htm or something like it. Thanks for the info in advance!