Nifty Jr has outsmarted Nifty 50 for quite some time now. This may well coincide with the theory that not all large cap stocks will perform at the same time. Nifty 50 has been mostly driven by a few countable stocks like Reliance, TCS, HDFC, etc. If you can spot such stocks you can also outperform Nifty 50. On the other hand Nifty Jr has cumulatively and steadily progressed better than Nifty 50.