What seems to be lacking are ideas for, for want of a better term, "magic guns". Perhaps this is a lack of real-world analogues. There is no firearm equivalent to Excalibur, for example. The nearest you could get with iconic firearms tend to focus more on the user - Patton's pearl-handled revolver, a six-shooter belonging to Billy the Kid, Dirty Harry's Magnum .45. Others are sort of iconic in a generic way, like the Tommy Gun used by all 1920s gangsters (in Hollywood if not real life), or the Winchester rifle.
But that doesn't mean they couldn't be incorporated into a game that fully embraced firearms and magic. A "magic bullet" blessed to kill a single enemy, for instance, or a rifle with accuracy over an incredible distance. A pair of duelling pistols that belonged to a great swashbuckling hero that now have some mystic powers, even just applying the standard magic weapon abilities to firearms - a Thundering Blunderbus ("Roaring Meg") for example.
Anyone done any such thing in their games? Or come across any supplements that feature such an idea?