Back Sight: All metal.  This is an odd one, the actual sight is great but the way it fixed to the receiver is not so good.  The fixing is by a screw that tightens a block against the sight.  This would work well but the block wobbles a bit, so the sight can wobble a lot.   I fixed this by putting some cotton between the block and it’s fixing.  The biggest problem the back site is that it is made from a soft metal and bends easily.  I’ve also been told that the paint used can change colour over time, but a quick spay should be all that is needed to rectify this.  The actual sight itself it the best I’ve seen in Airsoft.   It has an AK style button that will move the V bar up and down in big jumps.  It has a winder that will move the V bar in smaller increments for fine adjustments.  It has a range marked slide that is held in by a small screw for adjustment when zeroing.  No windage adjustment, but hey, it’s a Medium machine gun not a sniper rifle ;o).  As sighting a target the V bar and long front sight make it incredibly quick to aim (if you can move this weight beast fast enough ;o) ).  All in all I love the sights, best I’ve used on a stock AEG, and most fun to tinker with.