I know these were out of stock for a while but they are back up now! Get them while you can!
http://www.aimsurplus.com/product.a...23/5.56+AR/M16+Bolt+Carrier+Group&groupid=723
http://www.aimsurplus.com/product.a...23/5.56+AR/M16+Bolt+Carrier+Group&groupid=723