well duh a portable crank powered gatling gun as that would fit the period or a naval cannon yaeh I checked gatling gun has popped as a suggestion earlier than my suggestion but I'm still hell-bent on one class like the Soldier getting a 1850s cannon
considering the time period I'd like to see the Soldier shouldering one of these bad boys and using it as a rocket launcher http://en.wikipedia.org/wiki/Carronade who said naval cannons can't be rocket launchers?