I bought a 91/30 a couple of months ago.  I just realized to day that the rod that threads in place under the barrel is shorter than the barrel.  It's got a hole in the end to accept a patch but a cleaning rod shorter than the barrel doesn't seem like it's going to do much cleaning.

 

What is it really for?

Dipstick?

Actually, it's not all that uncommon to have surplus rifles come with wrong parts.

I'm not a Mosin expert, but possibly the cleaning rod is from another model wit h

a shorter barrel?

 

Additional explanation here: http://www.shootersforum.com/ex-military-rifles-cartridges/47731-clean-rod-mosin-nagant-m44.html

 

The rods of two or three rifles were typically joined together to make a rod of sufficient length.  Similar to how the US military issued each GI a "half tent" kit.

 

Cleaning rods for many bolt action military rifles were assembled from several rifles as dig0770 described. Mausers among them.

you have to add the other pieces to it to make it the right size like djg shows. I don't recommend using it because a steel rod will wear out the end of the barrel if not used carefully and properly. also i have had shells from surp ammo crack and expand in the chamber. take the rod and throw it down the barrel and it busts it out. 

To roast marshmallows on a bonfire...

To clean out your barrel with some diesel fuel after you're done fighting Nazis/Finnish/Chinese/Bolsheviks/Communists/Afghans/whoever else, because the five people who used your rifle before you that day probably didn't clean it.

 

Also, I don't see how the rod can be connected to another rod.