I don't understand the fascination with "bump fire" or "slide stock" rapid fire systems. You have to hold the weapon in your shoulder (or waist) "just right" and have the trigger pull "just right". Those positions are generally not considered proper form to deliver accurate rounds on target. I guess it's fun to see/hear the simulated FA fire, but as far as delivering accurate fire on target, they are only gimmicks. Better to train delivering accurate double and triple taps on multiple targets than blazing through 25 wild rounds.