Which would include me. Here's a good post on the arf.com site that explains a lot. Read it all, follow the links and read those posts. It covers a lot of the questions I've had and that I've seen asked around on this board lately.
http://www.ar15.com/forums/topic.html?b=3&f=118&t=342873
http://www.ar15.com/forums/topic.html?b=3&f=118&t=342873