I've never shot one, but I've been in a Humvee in which a guy was firing one from the turret at a possible IED up ahead.
Between the brake and a lack of ear plugs and the confines, of the humvee, I felt like I did in football after getting concussed. Kinda woozy, a little nausea, slight headache.
Strangley, it was worse than when the turret gunner would rock and roll on the M-2.
NRA Life Member
Big Sister: "You should be sponsored by Allen"
Me: "If you can't shoot good, at least look good walking to the firing line."
Big Sister: "Can you not afford a Pelican? Then buy an Allen gun bag."