I told a friend at work about this post. He said that his friend, a deputy for the sheriffs department, bought one a while back, to use as a back up gun. They took it to the range to fire it for the first time, and not even through the first mag, the same thing happened to him. He said the slide just came off and went downrange a few feet. He said it was a 9mm ADP.
I wasn't there to witness it, but that is the story he told me.
Sig P220 Stainless Elite 10mm, GLOCKS- (19 Gen 4, 20SF, 21SF, 30SF, 42, 43), Beretta 21A Bobcat, Patriot Ordnance P415, Patriot Ordnance P308, Sig 556 SWAT Classic, Colt LE6920, Kel Tec KSG, 6.5X55 Swedish Mauser CG 1903 M96/38, 6.5X55 Swedish Mauser CG 1908 M96, Swiss K31 7.5X55, BNZ 42 K98, Ruger 10/22 50th anniversary design contest rifle, Tikka T3 CTR .308, Tikka T3 Lite .30-06, Winchester 1200