Over at The Firearm Blog, there are some new photos of what appears to be a modified Chinese Type 81 assault rifle designed to fire rifle grenades, sighted in the hands of the Kachin Independence Army (KIA) in Burma. It seems likely that this is a craft-produced weapon, modified locally. The grenades themselves, seen in this image, appear similar to Norinco DQD 1 rifle grenades. 

As they note over at TFB, China is a well-known supplier of the Kachin Independence Army.