Spoke with a gun dealer today and YES the Glocks are on the approved list for Mass, HOWEVER, Glock still needs to send sample guns in for the final approval to the AG's office. Until that time, even though they are not on the list they CANNOT be sold in Mass just yet..(GO figure, only in MASS.)...
As far as the Glocks exploding, I had one damaged which was contributed to a round that was fired that had extremely high pressure from factory ammo. In their case I would have to look at the ammo first, 3 guns in the same day being defective I would have to doubt, high pressure would do it. Thats why we all know that you NEVER fire reloads in a semi-auto handgun (which I doubt they did).
Just my thoughts,
Ed