I have been trying to find this Lego Piece for a while now and I just can't seem to find it. I saw this Lego Warthog MOC on Youtube by hachiroku24 and wanted to build it, but I can't seem to identify the main part of the turret. The piece is the black one in the lower middle and I can't seem to find it anywhere. Anyone have any ideas?
Here's the video URL for a better look at the piece: