Nouns

(n)automatic rifle, automatic, machine rifleself-loading rifle capable of automatic fire
(n)automatic pistol, automatica pistol that will keep firing until the ammunition is gone or the trigger is released

Adjectives

(a)automaticoperating with minimal human intervention; independent of external control“automatic transmission”, “a budget deficit that caused automatic spending cuts”
(s)automatic, automatonlike, machinelike, robotlike, roboticresembling the unthinking functioning of a machine“an automatic `thank you'”, “machinelike efficiency”
(s)automatic, reflex, reflexivewithout volition or conscious control“the automatic shrinking of the pupils of the eye in strong light”, “a reflex knee jerk”, “sneezing is reflexive”