AK-47’s mounted on Chineses artillery barrels

A photo in the NK AAA article I recently blogged about show AKs mounted on artillery barrels. The theories on MilitaryPhotos.net are that they could be:

• Crude Sights
• Used to fire tracers
• Used to fire bullets during training instead of artillery rounds to save cost.

The only other explanation I can think of is that they are just stowed away up there. Although I don’t see how the operators could climb up a hot barrel to fetch it during combat.

Anyone know what they are really there for?