Talk:12.7mm Single Machine Gun Mount/@comment-2601:18A:C500:55E0:2D6F:FD20:5658:D236-20170725203934/@comment-129.2.181.90-20170919051008

http://www.navweaps.com/Weapons/WNBR_5-62_mk3.php

It's the .50 cal Vickers.