Toshiro Mifune's character, Kikuchiyo, travels to the bandits' camp and steals one of their two remaining fuselock muskets. Shortly afterward, the bandits fire twice at the samurai within five seconds with their last firearm. A fuselock takes as much as two minutes to reload, prime, and fire.
In some instances in the film, such as when Gorobei kills the bandit who was checking the water level with an arrow, the actors were actually shot with real arrows. The actor would simply wear a block of wood under his costume (which you can see if you know what to look for) and an expert archer would actually shoot him.