Ah the Europeans, in particular the 19th century French aristocrats who first created a panoply of hidden firearms. Barrels and bullets or shot shells all decoratively ensconced in anything from 19th Century Imperial ring guns to pipes that fired a bullet to walking canes that acted as swords or guns.
Above: This 19th Century gun cane fired .410 shot shells which allowed it to remain light and relatively thin. The trigger folds out for use and down and away otherwise.
Above: This was apparently called the Under Hammer Cane Gun. It fired a 56 gauge slug and retails for over $2000 in working condition.