Cub Driver wrote in message . ..
An army
machine-gun bullet wouldn't fit a navy machine gun nominally of the
same caliber.

There was just one exception; both services used the licence-built
German 7.92mm MG 15 flexible gun (although they used different
designations...).

What is even more suprising is the lack of standardisation WITHIN each
service. I put a photo in 'Flying Guns: WW2' showing all of the
different aircraft ammo of up to 20mm which they used in service; the
IJN used five different calibres, the IJA used six, and the only
common element was the 7.92x57. There were also three different 30mm,
three different 37mm...

Tony Williams
Military gun and ammunition website: http://www.quarry.nildram.co.uk
Military gun and ammunition discussion forum:
http://forums.delphiforums.com/autogun/messages/