Robuta

https://www.war.gov/Multimedia/Photos/igphoto/2002027227/
A U.S. Marine assigned to the 13th Marine Expeditionary Unit embarked aboard the amphibious assault ship USS Boxer (LHD 4) carries a .50 caliber machine gun...
machine gunmarinecarriescaliber
https://www.nps.gov/places/000/weapons-of-war-wayside-gun-deck.htm
gun decknational parkweaponswarwayside