A muzzle-loading firearm having a barrel and a pivoting firing mechanism. The barrel has a breech plug, a pivoting junction axle. and a blocking axle, and the firing mechanism has a trigger, hammer, striker and notch. The firing mechanism is pivotally attached to the barrel at the pivoting junction axle and the blocking axle is movably aligned in the notch. When the firing mechanism is pivoted, it is guided by the blocking axle in the notch ensuring sufficient clearance between said firing mechanism for easy placement of a percussion cap.