Re: Chamber suggestions for .308
You can use a standard SAAMI spec chamber reamer with good results, you can use a custom reamer or anything in between. Once of the things I like about teh PT&G reamers is that as long as I take care of them they seem to stay sharp. Sending a reamer off to have it sharpened costs money and causes down time which equals either lost profit margin and/or higher prices.
I've heard good stuff about Manson reamers too, I just haven't don't have personal experience with them so I can't recommend them.