I haven't seen any cylinder explosions, but some of the Gamers in USPSA competitions have loaded some rounds so lightly that they have to point the muzzle up and shake the pistol to make them fire.Adding some kind of wadding would be a good idea; I didn't see where you were doing this, but I could've missed it. Back in the '80s or '90s, I read an article about guns blowing up, and it came down to light powder loads. The light load had so little powder in it that it exposed the flash hole, so instead of the primer igniting a small amount of powder and that propagating out, it basically ignited the powder along the length of the cartridge, resulting in a detonation. They were using a wheelgun (.38Spl, IIRC) for the testing, and it blew the top of the cylinder off and peeled the topstrap forward. It was some baaaaad juju.
I know a guy that hasn't been on here for awhile that went to a National that got disqualified because they wouldn't point the pistol up and shake.