aic-armor:

Combination Hunting Dagger and Double-Barrel Percussion Pistol, Sheath, and Belt of Emperor Maximilian of Mexico, Joseph-Célestin Dumonthier, 1854, Art Institute of Chicago: Arms, Armor, Medieval, and Renaissance

In 1840 the Parisian gunsmith Dumonthier patented his popular hunting knife with double pistols. This weapon artfully combines two percussion pistols with a knife. The hunter used it to deal the final coup de grace, or mercy blow, to the wounded game.
The crowned monogram engraved over the silver-gilt belt buckle has been identified as belonging to Maximilian, the short-lived Habsburg Emperor of Mexico. The monarch apparently practiced the European court tradition of hunting in Central America.

George F. Harding Collection
Size: L. 33.4 cm (13 1/16 in.)
Blade L. 22.1 cm (8 13/16 in.)
Wt. 1 lb.
Caliber .36

Medium: Steel, brass, silver, gilding, leather, silk velvet, and silver-gilt thread

https://www.artic.edu/artworks/106235/