an automatic gun that can fire a lot of bullets one after the other very quickly

[ before noun ] Several reporters were caught in machine-gun fire. 几名新闻记者遭到机枪的扫射。

to shoot someone with a machine gun

The raiders machine-gunned everyone in the bank before escaping in a van. 抢劫者用机枪朝银行里的人扫射了一通后乘一辆厢式货车逃离。