Peaceful isn't the right word, obviously. Quiet isn't exactly correct either. Cathartic may be closest. That's what it feels like to see a fully automatic assault rifle be fired in super slow motion. The bullets come one after the other in a relentless barrage but there's a certain amount of detachment to its power and danger. It's like being hypnotized in trying to figure out how the machine works as opposed to being in fear of its power.
The Slow Mo Guys shot themselves in slow motion shooting a M4 Carbine. The gun can shoot 30 rounds in just over 2 seconds so what you're seeing is a very, very slowed down view.