Mod:DUST Survival Simulator/And Stay Back

"'You've discovered a Shotgun technique that has a chance to knock an enemy back.' —Fallout: DUST and Fallout: New Vegas description "And Stay Back is a perk in Fallout: DUST and Fallout: New Vegas introduced by the Dead Money add-on. 

Effects
And Stay Back introduces a knockdown chance, if the following weapons are used:
 * Caravan Shotgun
 * Big Boomer
 * Dinner Bell (probably not obtainable in DUST)
 * Hunting Shotgun
 * Lever-Action Shotgun
 * Sawed-Off Shotgun
 * Single Shotgun
 * Riot Shotgun