Just added a strange marked 20x102 round to my collection.
It is marked 20mm T153E1 - Type Steel - FA X20-2513
Projectile’s driveband is marked *HVM-20-61 54 20MM T283E1
Case is steel with percussion primer
As far as i can find the T153E1 was a 'Cartridge, Experimental, Practice, 20mm (Percussion Primer; 1600 grain projectile)'
No reference to the ‘type steel’ marking or steel case nor to the M283E1 projectile being used on the T153E1 cartridge…
A google-search learned me that in 2002 a similar ‘FA X20’ round with T283E1 projectile was sold, with diffrent lotnumber and same year of mfg (54) but that one didn’t had a primerpocket at all, and the case was brass…
Unfortunately the pictures are gone from that add.
I hope anyone has more info on this round/markings.