This video isn't all that good.
Basically in a captive suppresion match you start with any sniper other than the vsv-39.
Then basically get killed.
While dead open your weapon menu and change to ANY assault rifle/maching gun, but DO NOT HIT X OR O. Doing so will not allow the glitch to work.
When revived you will have whatever weapon you chose, but everyone else sees you as having an automatic sniper.
=D