Today’s Photo is of the brand new Heckler & Koch MR223 A3 GZ.
GZ is short for Gurtzuführung, which is German for belt-fed.
This construction will bypass all magazine restriction, as there is no magazine.
Well it would be nice if it was true, but it is not. It is just a normal HK MR223 with the belt in a very strange position.
If you want to belt-feed your AR15 there are however some solutions like the Fightlite MCR Belt Feed AR-15 Uppers. Check here for their webpage.