The second video is of the first version, supposedly much more kick/recoil in the new one (as in the first video). Yes, the second version is shown without it being attached to the upper, but I'm sure that it still has more kick when assembled fully.
Can't wait for the Escort box to come out, but for the AK. Escort box+my ICS bolt=good fun.
Large pic here:
http://i10.photobucket.com/albums/a1..._gbb2_1401.jpg