I just wanted to post up some reading for you guys. This is a link where I got to talking about the .260 vs. the .308 in an AR platform. I DO understand that the .308 is not an option since you do not want to buy a complete rifle, but I did want you to see just some of the discussion that went on about the .260, 6.8 and 6.5 Grendel. PLEASE PLEASE PLEASE look up the ballistics and compare things the way that I do in some of these posts. Don't take just everybody's word on how cool and hot rod these calibers are, because they're not necessarily the best thing since sliced bread. These calibers have their place, just know their limitations and what you're getting yourself into.
http://www.pafoa.org/forum/rifles-42...-a-page-2.html Also here is a discussion on XDtalk, sorry for cross posting to other forums, but it does have some good info about the 6.5 Grendel. Here's that link
http://www.xdtalk.com/forums/ar-talk...endations.html
Also realize that if you go with the 6.8 spc and you handload, you'll be really really limited in what brass and bullets that you buy. The 6.5 has a few more choices in bullets and what not, but you'll still have to fireform all your brass if you are reloading. Just some things that you should think about before you just jump right into some of these. Hope this isn't too far off topic, I just want you to know some of the facts.