http://www.picturetrail.com/sfx/album/view/17546456
You will note most of the barrels are fluid steel, and ruptured from an obstruction



I've posted on several forums the offer of $100 to anyone who will send me a pattern welded barrel that 'unwound like a spring'. Welds can fracture however.



There have been several threads on trapshooters.com about blown up K-guns. Every instance has been with handloads.