The Germans actually produced a few working firearms with angled barrels during the second world war. They were used in conjunction with a sort of periscope for firing over the top of trenches and around corners. It wasn't something that was made in great numbers, or carried by every soldier on the field, but they [i]did[/i] make some and they [i]do[/i] work. I don't remember the designation for the weapon, but with a little help from Google I'm sure you'll find what I'm talking about. Assuming of course that you care to look it up.