Hello, I am new to this forum, but have been reading on hear for a couple of years . I am looking at getting started in the local prs matches hete in south texas. I am very interested in the 224 valkyrie. I have been reading a lot about this round on this site and many others. I have never owned an ar-15. Any help would be greatly appreciated on a parts list for a build , a complete upper, or complete gun. I have reading that rock creek barrels seem to run a little faster. If this is not the case, please advise. I also was thinking about a left side charging upper .