Bistool mai sarrafa kansa nau'in bindiga ce da ke harba zagaye ɗaya a kowane jan hankali sannan ta sake loda zagaye na gaba kai tsaye cikin ɗakin. Tana amfani da kuzari daga harba zagayen da ya gabata don cirewa da fitar da kwandon da aka kashe, sannan ta loda sabon harsashi daga mujallu zuwa dakin harbi. Kalmar "semiautomatic" tana nufin cewa bindigar tana buƙatar wani nau'i na daban don kowane harbi, amma ta atomatik tana yin wasu ayyukan da ake buƙata don shirya zagaye na gaba don harbi.