it has to be pump.
Obviously i can't lift directly from gun designs as they're copyrighted so I need to make an 'inspired' mix of a few.
Copyright might not be an issue. Some pump action shotguns are older than dirt.
The classic Winchester Model '97 comes to mind. (Using it might make "Smokin Guns" jealous
)
http://en.wikipedia.org/wiki/Winchester_Model_1897Hammers too retro? The model 97's successor looks modern and still is almost 100 years old.
http://en.wikipedia.org/wiki/Winchester_Model_1912I don't know that they would suit Dave, but both designs had "riot gun" variants for the military.