The Case of the Linked Round--Why is this?

http://die-less.com/2011/12/01/the-case-of-the-linked-round/

I found these pictures of dudes with one or more linked cartridges clipped onto the barrels of their AKs. One guy swears they're there to cook off and become magic bullets, but that seems unlikely since they're sometimes behind the front sight block.

Anyone have a better idea?

Anyone have more pictures of this?