20mm I.D. please

[dano1917]

I picked up this 20mm shell in a trade a few months back. I was "playing" with it and found out that the bottom screws off. Why is this? For adding ballast? stamped on bottom is CARTRIDGE DRILL MIRAL 20MM and something else I can't make out. Obviously I don't think this is a Vulcan and you could call me the 20mm virgin. Any info appreciated..Dano

 

[HAZORD]

Looks to be 20mm X 110 Hispano aircraft gun drill round.

 

[dano1917]

microfilm

Thanks Hazord, appreciate it, thought maybe bottom screwed off to conceal microfilm!!!!!!!! Hold that 57mm fuze 4 me please......Dano