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.
Many years ago, when I was a beat cop, I carried a Colt Mustang .380 ACP as my backup gun every day. A while back, when I was practicing at the range with this same gun, I noticed that once the pistol had a few rounds through it, the trigger got increasingly harder to pull and finally failed to fire at all after several magazines were run through it. Not Good!
Galco changed the bellyband concept with the new Underwraps Elite, which allows concealed carry of a handgun and accessories around your midsection with myriad options for the pistol's location, added comfort and the ability to carry EDC accessories like spare magazines and a flashlight.