I think unless yer absolutely lucky as hell you try to quickscope a real modern sniper rifle you will be missing teeth.

you might get away with trying it with an AR 5.56/223 but you won't hit the broad side of a barn.

I know with my M&P15 (m4 Clone) at 100yrds you can't hip fire.

you must shoulder it steady aim and if you can get two or three rnds downrange and hit the ten spot in a few seconds yer doing dang good.