Edit: wrong quote, meant to quote @GJM
way back in 2010 when I ran 2100 rounds through a 5" Pro Center gun in slow fire I'd occassionally get a case that would just clear the port and land upright on the case and just stay there balanced like I'd placed it there.
I loved that pistol for awhile until dead trigger and of course soccer ball sized groups at 25 yards. I could really get my blaze on with it though.