I would really like to do an AR in 7.62x39 but with the lack of quality magazines that carry more then 10rds kind of takes the fun out of it. Right now the Oly upper in 45cal sounds the most appealing to me, but then do I make AR rifle or AR pistol? Really like the AR pistols, I have 2 now in 5.56 now in 7" and 10.5