Assertion: early machine gun | /r/HasProperty | water-cooled
Facets:
value: often
type: DEGREE
Source sentences:
text: Early machine guns were often water-cooled; while this technology was very effective, (and was indeed one of the sources of the notorious efficiency of machine guns during the First World War ), the water jackets also added considerable weight to an already bulky design; they were also vulnerable to bullets themselves.