20x102mm question

I picked this up at SLICS this year. My question is would this be one of the earliest headstamps for this caliber? Is this a common headstamp or a hard to find one? I seem to remember reading somewhere that the 20x102 was developed in 1952.


Hi Zac,

The first “20x102” i have in my collection is a .60 cal case, necked out to 20mm with a reworked 20x110 projectile.
it has a reworked M99 and T61E1 marked projectile, with HS ’ * F A * 48 ’ .
(you can see some detail pictures here: )

I had never seen an ‘LC 52’ Headstamp, but it might indeed be one of the early standarized production cases.


Bits of Lake City Army Ammunition Plant history relating to 20mm production circa early 1950’s:

From The World War II Ordnance Department’s Government-Owned Contractor-Operated (GOCO) Industrial Facilities: Lake City Army Ammunition Plant Historic Investigation (1995 – 1996):

The M505 fuze mentioned above was used with HE/HEI projectiles intended for the 20 x 102mm cartridge.


Thanks guys.