How do you plan to block the gas port? It would seem to be the best and easiest way to get a straight pull AK. On an AR type I think it would be a bit simpler - there is already a pin through the block that holds the gas tube, so you can just pin in something solid into the block. On an AK, the piston rides inside the tube, and the block is pinned to the barrel (like the AR in most cases). Seems like it is going to take some modification of the gas block on the AK to get the gas shutoff. Just wondering how this is usually done.