Dueling Pistol

 is a gun that fires large, piercing musket balls which bounce twice.

Trivia

 * The synergy is likely a reference to Van Helsing, the vampire hunter created by Bram Stoker.
 * The synergy is likely a reference to the death of Abraham Lincoln, who was shot with a Derringer, and the Dueling Pistol likely is referencing the many duels that Andrew Jackson had in his lifetime.