Available on the app store for 99 cents: http://tinyurl.com/silverrevolver
Silver Revolver gives you a fully digital, non-lethal reproduction of a chrome handgun. Not only can you spin the barrel, but you can selectively fill it with up to six bullets and fire them with a realistic, resounding shot by touching the trigger. When the barrel is empty, just shake to reload, and you’ll be set to fire more shots with the vibrating trigger.
In the preferences screen, you can take full control of your Revolver by choosing whether it should vibrate upon shooting, auto reload when the barrel is empty, or fire when you shake your device.