Abstract: A single-shot rifle having a barrel unit and a butt-box unit consisting of a box, a butt having a butt axis, fixed to the box, and a butt-plate fixable to the butt is provided. The barrel unit is detachable from the butt-box unit. The butt-plate is manually rotatable between a use position and a rest position and the barrel unit is laterally couplable to the butt-box unit. The single-shot rifle with separate parts is insertable into a substantially rigid tube for carrying the weapon. The tube and the single-shot rifle housed in the tube form a floating, waterproof assembly.