Strange Guns: Czech Live Fire 7.62×39mm Training Rocket
Oddly enough the below ‘rocket’ is actually a rifle chambered in the 7.62×39mm cartridge! It is used in a RPG launcher for training purposes. I assume that it would be used in an actual RPG launcher and not a training replica.

I came across this link a PFOA post. From the website that sells it:
Used by the Czech military as a training aid to simulate firing a rocket propelled grenade using 7.62×39 ammunition. Features blued-steel construction with a rifled barrel, bolt assembly, knurled grips and yellow rocket head. The push-button type trigger assembly is designed to be fired while inside the RPG launcher itself (launcher not included or available), but it can be fired manually by depressing a small lever and pressing a recessed button in the rocket body.
Here is a video of it being fired:

Yep, I used one of these, but “mine” was Romanian made, camo green instead of the stylish yellow. I served in the Romanian Army in the eighties. The gizmo would load in the barrel of the actual weapon (not a replica, just like your article suggests). It was single shot and supposed to help train your aiming skills without ruining the army’s budget. We laughed at it a lot. Shooting that menacing-looking RPG and making a minuscule hole in a xerox-copied tank silhouette had something funny in it. Needless to say, there were no exhaust gases either. I shot it once only – we were quite under-trained, you see. Our main goal in the military life was to pick up potatoes or corn or help some crumbling factory that had no workers. Ah, the eighties in Romania
I used something similar for training with the AT4: http://en.wikipedia.org/wiki/AT4
But that one used a 9×19mm tracer round, so you could see the arc of the projectile, which supposedly was matched to simulate the live HEAT round.