One was the Objective Crew Served Weapon, now known as the Advanced Crew Served Weapon and designated XM307; this is a machine gun in 25 mm calibre.是什么意思_One was the Objective Crew Served Weapon, now known as the Advanced Crew Served Weapon and designated XM307; this is a machine gun in 25 mm calibre.在線(xiàn)翻譯_英語(yǔ)_讀音_用法_例句