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, Ruger LCP, GLOCKS- (19 & 29 Gen 4, 20SF), Beretta 21A Bobcat, Patriot Ordnance Factory P415, Patriot Ordnance Factory P308, Sig 556 Classic SWAT, Sig M400 11.5", 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, French MAS 49, Ruger 10/22 50th anniversary, Tikka T3 CTR .308, Winchester 1200, Weatherby Vanguard S2 .223 Varmint