The Marines fired back with a grenade launcher.

海军陆战队用手榴弹发射器反击。

《柯林斯英汉双解大词典》

The XM29 was intended to be a shoulder-fired, semi-automatic grenade launcher in 20 mm calibre and to incorporate a compact, lightweight 5.56 mm rifle as a back-up weapon.

XM 29确定为一种抵肩射击，20毫米口径单发自动榴弹发射器并结合一个紧凑型，重量轻的5.56毫米步木仓做为后备武器。

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On other convoys along those same roads, Marissa's husband, Specialist Charlie Bootes, manned a Mark-19 fully automatic grenade launcher.

NPR: Waiting and Dreading: Families in War Time

Because they're an exact copy of another grenade launcher that's virtually identical.

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There were no heavy machine guns, either, nothing larger than a Kalashnikov, which meant that the new patrol base could be outgunned by any Taliban soldier with a grenade launcher.

NEWYORKER: After America