 The most common type of pistols in modern times is the semi-automatic pistol, while the older single-shot and manual repeating pistols are now rarely seen and used primarily for nostalgic hunting, and the fully automatic machine pistols are uncommon due to strict laws and regulations governing their manufacture and sale.Sometimes in usage, the term "pistol" refers to a handgun having a single fixed chamber integral with its barrel, making pistols distinct from the other main type of handgun, the revolver, which has multiple chambers within a rotating cylinder that is separately aligned with a single barrel; and the derringer, which is a compact weapon often with multiple barrels.UK/Commonwealth usage does not always make this distinction, particularly when the terms are used by the military.