I'm butting in not because I think I know something, but because I'm in question. I looked at this rock river varmint at PK also. It sounds like a sensible buy, but when I read the page about frequently asked questions on PKs site, there is a paragraph about uppers. It says that the upper assemblies don't neccessarily use all the parts from the listed manufacturer, nor do they include all the parts unless specified in descriptiion. It says that the upper is sold under the name of the barrel used.
Now the varmint RRA upper says it uses the Wilson air guaged barrel. So I'm confused on what manufacturer of parts I'd be getting.
So it sounds very unscpecified what your getting for 600. If I were to call PK up, they'd spot me as being green, and I could be potential buyer to dump a bunch of junk on for 600. I'd probally be safer buying it from the factory and paying more. I wnt to the rra website, but it has a button called wishlist near most items. I'm assuming that means there out of stock. Anyway I don't mean to jack up this guys thread, but noone is responding to mine, and I was viewing the same varmint upper he is talking about.