How very unpleasant! As someone still smarting over a favorite backpack stolen with a favorite jacket in it (but I had fortuitously taken out the laptop the thief was no doubt after), I can sympathize to a degree, but that was only out of a rental car, not my new home! I doubt it's much consolation to imagine the thief's dismay at finding a bunch of sticks and cards rather than easy-to-sell electronics, but maybe some grim amusement will lighten the load somewhat.

I won't pile on with "there's likely a lesson in all this," as it sounds like you're already reflecting on that, and even if true, right after isn't the best time for such thoughts (and even if true, it still sucks!). The only thing I'd say along those lines that I haven't seen you or others say is that there might be a message in what was left - something like "focus on this stuff and what it means."

Other than divination, which you've already done, and prayer, like JMG suggested, I'm afraid I'm short on practical magic suggestions.

On a mundane practical note, and not to add worries to your plate, but did you happen to have a record of the gun's serial number? You might want to make sure that gets reported to the cops in the police report in case it gets used in a crime or something, since you'll be the last owner of record, and might get some unwelcome questions in that case.

At any rate, again, my condolences, and good luck continuing through this disappointment,
Jeff