The conversion from musket to breech-loader was done by milling open the barrel's breech section and inserting a hinged breechblock fastened to the top of the barrel. A thumb-operated cam latch at the rear of the breechblock held it shut when in closed position. The rack-type system extractor was withdrawn automatically as the breech-block was opened and snapped back at the end of its stroke. The firing pin was housed within the breech-block. The hammer nose was flattened to accommodate the firing pin.