20mm and 37mm ID help

A little help please. I’m not well versed in the larger calibers, so I need some assistance with the ID of two unfired projectiles. These items came from a gentleman who worked at the Raritan Arsenal in New Jersey during WWII. The first is a 20mm projectile from either the 20x110 HS or the 20x110 Oerlikon. My reference materials are not precise enough to differentiate the two types. Steel body, zinc? pot-metal/white metal dummy fuze/nose cap all painted olive drab green, copper rotating band. Stamped into the projectile body is “MK 3 - 54 U” (might be a “J”) “LOT 1451” “MAT”. What does this go to and is it a practice projectile or “ball” or what?
Second projectile is from the US 37x223R and appears to be an AP-T. All steel body with wide copper rotating band and an aluminum nose cap/windscreen that is threaded to the projectile body. There are two notches in the projectile body that appear to be for staking the nose cap in place, but this has not been done. The base is hollowed out for what would likely be a tracer cup. There is not trace of any paint whatsoever on this projectile, and it appears to have never had any. The only markings at all on this item is the leter “Z” on the base of the projectile. I assume that the loaded round would have an all-black projectile with white stenciling? Supposedly, the gentleman who owned these items was a book binder by trade and worked at Raritan Arsenal in this capacity making technical manuals and such. Apparently, other workers gave him these projectiles and they were used as “paper weights”. Could these have been produced at Raritan? Could the 37mm be incomplete/unfinished, taken off of the production line? What is the correct nomenclature for the 37x223SR AP-T, what gun was it useed in and can any one post a pic of what the round looks like?



Have you had a look on Tony Williams site ? quarry.nildram.co.uk/tankammo.html

I’m no expert, but perhaps a photo of the 2 types together would help?
The black (TP) projo is a 20x110 HS, than a UPE of the same. The 2 with flat noses are 20x110RB Orlikons

Edit, because I forgot to insert the photo, DUH.

What is the round on the far right in your photo?

2 bore hubel express “prototype” dummy.
The “little” one in the photo is the 458 Hubel Express (the smallest wildcat that bears his name).
Ed Hubel likes his wildcats to be on the “large” end of the scale.

What case is that 2 Bore Hubel Express round based on? What on earth is it supposed to be fired from?

27x145B with the belt rurned off and trimmed at the shoulder.
Knowing Ed, and I do, he’ll probably build some monster barreled thing to shoulder fire it from, should he decide to go ahead with the project.
We are getting way off the origional topic, but there’s a long process of trial/error & looking/thinking before a new wildcat ever sees the light of day. Having been to Ed’s home a few times, and having fired several of his “toys”, I sometimes end up with a experamental/prototype of his.

If not in hospital with a dislocated shoulder… ;-)