Судя по картинке - Полдюймовочка. Или даже - 4,2-линеечка...
Не-а!
Судя по картинке -- четырёхствольная картечница Норденфельда образца 1883 года. Калибр -- ровно ОДИН дюйм.
http://www.victorianshipmodels.com/antitorpedoboatguns/Nordenfelt/nordenfelt1inch4.html
A development animation of the
four barrelled Nordenfelt 1" machine gun of 1883. This gun was developed as an anti-torpedo boat defense, and fired a hardened steel bullet to a range of 1,500 yards, although its effective range was only 400 yards. The objective of this animation is to show the loading mechanism. No audio.