I don't have a definitive answer on what the deal is with the 6 position receiver extensions that Specialized Armament sells but Ken does list them with a Colt part number. I have two of them and the Anodizing on them is little lighter than the anodizing on my 4-position Colt receiver extensions; apart from that and the fact that they have six positions, they look identical to my 4-position Colt REs. My BCM receiver extension is close but that flat spot near the front is smaller than it is on my 4-position Colt and 6-position Specialized Armament REs. Top picture left to right: 4-position Colt and 6-postion from Specialized Armament. Bottom picture left to right: BCM and LMT.
http://i212.photobucket.com/albums/c...i/IMG_1451.jpg
http://i212.photobucket.com/albums/c...IMG_1453_1.jpg

