Gun modifications: What is a ‘bump stock’ modification and how does it work? - TomoNews

LAS VEGAS — The man behind Sunday night’s atrocity in Las Vegas had 23 firearms in his hotel, including 2 rifles modified with a bump stock, reported Popular Mechanics. Regular semi-automatic rifles require the user to pull the trigger to fire a shot. Bump stock modifications essentially eliminate the need for this. The modification absorbs recoil from the firing rifle, and uses it to bump the trigger into the shooter’s stationary finger. This combined with forward positional pressure from the shooter, allows the gun to fire at a rate closer to that of a fully automatic weapon.