I would not be too terribly surprised if some poor security guard at the East Nowhere C-ration cracker factory found himself walking his post with a Mosin, especially in 1942. 03s and Garands were in short supply, the 17s were mostly gone, and some purchasing officer may have turned to the cheapest thing he could find in order to equip his security personnel. BUT...in front line combat use? I doubt it.
Now in the closing few days of the war, I wouldn't be at all surprised if some of the US and Soviet soldiers meeting up had a few unofficial social shoots, at least until the officers showed up to spoil the fun.