Abstract: A bolt assembly is provided for a double-barrel firearm, such as a rifle or a shotgun. The bolt assembly is adapted to fit in the receiver of the double-barrel firearm. The bolt assembly comprises a bolt body which connects to first and second breech bolts, and which also couples to a bolt collar. The bolt collar has a bolt handle for operating the bolt assembly. The bolt body and breech bolts have recesses for accepting first and second firing pin assemblies. The firing pin assemblies include first and second cocking pieces, which are both cocked by means included in the bolt collar. Once cocked, the cocking pieces can be released independently of each other for firing using trigger means. Pulling the bolt assembly rearwards ejects the fired cartridges through an ejection port on the receiver. The receiver also includes a cartridge injector port which couples to a magazine capable of storing additional cartridges.