I think I may be building a 6.5 grendel soon. I first have a few questions. 1-Can I use a 5.56 upper rec. or is there a different one for 6.5? 2-What are the other names for the 6.5 grendel? I heard there are a few different names used by other companys so as not to infringe on the patent, i.e. "6.5 sporter". 3- What would be a good bbl that doesnt break the bank? Thanks.