The battleship Missouri

A five inch gun mount on the USS Missouri (now permanently in Honolulu harbor), which was crewed by my father while he was in the Naval Academy in the late 1940s.

The flamethrower

Probably the single nastiest weapon in the arsenal, the flamethrower can kill directly (by heat) or indirectly (by exhausting all oxygen in an enclosed space like a bunker); either way, not a good way to go.

The Sten

Homely as a mud fence, effective as a sledgehammer, the Sten (this is a Mark 2) killed more people in WW2 than any other pistol-caliber weapon.