Here you go Ted.
DDT HAS been demonstrated to occur with Smokeless Powder in an experimental setting.
To my knowledge (and I suspect the powder makers ain't sayin') it has NOT been demonstrated to occur in a shotshell
http://www.trapshooters.com/threads/smokeless-powder-ddt.245629/

Some humble opinions and SA sniping by the usual suspects here
http://www.trapshooters.com/threads/there-is-another-possibility-with-a-gun-blowup.50956/

http://www.trapshooters.com/threads/shotgun-blowups.244114/