As a Glock 21 owner myself, I've heard of the Glock Ka-Boom stories as well.
I seem to recall that they were guns in use by the Portland Police Department. For what it is worth, Glock seemed to have problems with the investigation results from the Portland PD.
Also, I've read that they were Gen 2 models, with less chamber support than current Glock 21s.
NRA Life Member
Big Sister: "Everyone in America is fine with the .30-30, except Mack. He has to shoot that .35 because that extra point zero fives inches will matter on Bigfoot."