Do any of our esteemed members have a site where a person like myself and my wife could read up on the essential basics about AR weapons. We are interested in making a purchase, but we know that we don't know enough yet to make an educated purchase. We need a through introductory primer on the weapons themselves, and all the different add ons that one needs for one of these type of rifles. I have had the Rock River ARs highly recommended, but don't even know enough to know if this is a good recommendation. Thanks for the time.