The Bump Stock (or Bump Fire Stock) device equipped 12 rifles of Stephen Paddock, the LasVegas killer, responsible for the death of 58 people and over 500 wounded.

This system allows you to easily convert a semiautomatic rifle into an automatic, by re-locating the energy of the shot through a rebound mechanism, the index then pressing the trigger and pressing the trigger high speed (in Las Vegas, the pace would have been 90 shots in 10 seconds)