Talk:12.7mm Single Machine Gun Mount/@comment-2601:18A:C500:55E0:2D6F:FD20:5658:D236-20170725203934/@comment-25459687-20170725210822

most of the HMGs used were the Hotchkiss 13mm, as far as I can tell.

http://www.navweaps.com/Weapons/WNJAP_13mm-76_mg.php

there were several types of .50 cal mgs used in airplanes, but not entirely certain about on ships.