Why is the spread so large for non-Nifty 50 shares or futures?

[kingsmasher1]

I use SL-M for everything.
For buy/sell=SL-M
for SL order=SL-M

I used to use SL-L,but order used to remain unfilled.

Yup, that is the problem with limit orders, it might remain unfilled if it is not amongst the best bids/offers out there, or if the market is trending fast.

SL-M is generally what i used to take as well, for quick intraday trades, and since i preferred Nifty50 stocks, so the spread was not much of a problem for me.