For a few years, I used to fire it in an indoor range. It was kind of cool because the muzzle blast was so powerful that the ceiling tiles would come apart and the shooter would be rewarded with a little "snow" shower with each shot. The concussion is so strong that the shooter feels a bit of a shove against the chest. The sound is more of a "ka-boom" thud rather than a sharp "crack". Because the weapon is so heavy and gas operated, the recoil isn't an issue except when trying to do double-taps.
I used the .50 when qualifying for the CHL. They moved me down at the end away from everybody.