Seems that the QBU 191 has a different muzzle device than the QBZ191 or 192, is there a guess as to why the change was made?
No, it's new. It's a transparent magazine for QBU191, which is the same as QBZ.
Does anyone know wich materials the DBP191 5.8x42 is made off? It seems to be a green coloured steel. Im not sure if i read somewhere that it had some antirust coating that reduces cost.