Need help identifying weapon on National Geographic Special

Watched/viewed the National Geographic Special on private contractors in Iraq. Saw an unusual AK47 type weapon used by one of the British contracted which I have never seen before and am hoping someone can help me on the specs and the nationality of the weapon. The weapon in question was used by one of the British contractors and was called an M21. It appeared to be 5.56 caliber and had a stamped AKM receiver, a Galil stock and front sight/gas block. This is a very interesting weapon. At first I thought it was a Galil SAR. However it did not appear to have the rear sight on the top cover. This is a very interesting configuration. I was hoping maybe someone on the site could give more detailed information.

Serbian AK in 5.56, I believe.

M_P

Yup, Pirate got it.

http://www.zastava-arms.co.yu/english/vojni.htm

I saw that special. I believe it was a serbian. In fact I saw that special twice and it seems when the contractor was loading up to go out on a mission he mentioned it origin.

LOL, looks like that guy might have a problem shooting his grenade launcher with that flashlight or laser right in front of the muzzle like that.