You've got some good reloading equipment, now you just need some good brass. As suggested above, it'd be a good idea to go with the likes of Lapua. I've seen plenty of Lapua 6.5CM brass available at decent prices to, so that should be a problem.
I have Hornady brass for both my .308 and 6.5PRC RPR's and I don't like them for their inconsistencies. If you don't want (or can't) get quality brass, then you should consider weight sorting your Hornady brass. There is some correlation between case weight and volume (though not a direct correlation by individual cases). Also, you didn't say what powder and bullet you're using as this can be a factor too as some powder and bullet combinations just don't work well together.