martinbns, I have invented a simple universal broken shell extractor that should be able to remove what's left of the broken shell in your chamber.
Buy a brass rod from you local hardware store which are somewhat smaller in diameter than your bore diameter. Then with a file create a hook at the end of that brass rod, as well file away an taper some of the metal towards the hook.
You will, when you insert the rod from the breach into the chamber, be able to "feel" when the hook at the end of the rod go over the borken case mouth, and then with a gentle pull, you should be able to pull out the remaining broken shell from the chamber.
Good luck,
Snowhunter