While a thorough cleaning should be enough to eliminate stubborn rimfire brass from failing to eject from a .22 LR Colt Diamondback, soaking the chambers with a penetrating lubricant like Kano Kroil should remove any leftover firing residue and restore positive extraction.
Is it my fault? Maybe. You see, two years ago when Colt introduced its new Python revolvers at a Gunsite media event, I was let in on a secret. After signing my life away in a non-disclosure agreement, I was told the next revolver would be an Anaconda chambered in .44 Mag. (it was) and, following that, a 2.5-inch-barreled Python.