ARES Arms & Munitions looks at this interesting weapon. It's in a size of a 7.62 weapon but fires a 35X32 SR mm cartridges, a bit smaller than US military's 40mm
http://www.armamentresearch.com/ares-arms-munitions-brief-no-1-the-chinese-qlz87-automatic-grenade-launcher/
From: ARES Arms & Munitions
