The WJ/FBQ-08 is seems to be a PAP (or in its new name, CAPF, China Armed Police Forces) only weapon. Break-open design like the old American M79 from the Vietnam War. The PLA (or its new name CA, China Army) is working on a side-open design like that of H&K and FNH for their 35mm grenade. It's marked with WJ (Armed Police) in its designation.
Its was minimum informations about this weapon, I'am not sure about the caliber or other.