Here is the ultimate beer shotgun opener keychain. This 3 in 1 device is great for opening bottles, opening can tabs, and putting a nice shotgun hole into a beer can.
Opening a bottle was not a problem, nor was opening a can. The one concern I had was using the shotgun portion of it on harder cans, like Heineken, but that worked great too. You can store this easily on your keychain.
Check it out at: http://www.drinkinginnovations.com/