By Zarax

Since WG introduced the uranium hartkern ammo for the 30mm MK 103 I started researching on the topic.
Trolling from SerB aside, it turns out to be a quite complex subject.

With tungsten imports getting more and more difficult germans started looking into alternatives and in the book "Inside the third reich" Speer himself states the following:

"In the summer of 1943, wolframite imports from Portugal were cut off, which created a critical situation for the production of solid-core ammunition. I thereupon ordered the use of uranium cores for this type of ammunition. 27 My release of our uranium stocks of about twelve hundred metric tons showed that we no longer had any thought of producing atom bombs."

The use of uranium cores in german ammunition was suspected for a long tome, during A-10's GAU 30 development we find the following:

In AFATL-TR-84-03 Historical Development Summary of Automatic Cannon Caliber Ammunition:20-30 Millimeter (ADA140367) Dale M. Davis in pgs 44-47 makes the point that he believes the Germans used Uranium-cored projectiles in the 30x184/30x185B aircraft cannon against Soviet tanks

In 1956 Aberdeen Proving Ground published the Handbook of German Aircraft Ammunition; on page 58-59is their drawing of 3 cm H-Panzergranatepatrone L'spur O. Zerl, a 350 gm projectile at 960 mps,at 300 m it would penetrate 100mm@0,70mm@30. O. Zerl=without fuze.

Mr Davis gives 7 points why this is an uranium core. I won't give all 7, but some of them are: H-Panzergrenatpatrone (special armor grenade cartridge) with no explosives inside.

Another note says special projectile with added incendiary effect, with no incendiaries inside. 100mm of penetration is more than any steel core would do.

It was described "Exclusively for attacking medium and heavy tanks. Practice firing prohibited".

Deep digging on the internet also gave a 37mm round with very similar properties to those described:

This started my search for the experimental usage of uranium cores in other rounds.

This is the report from GAU development:
The holy grail of german WWII historical research "Germany and the second world war" mentioned tests with uranium cores in 1944 but sadly goes no further:

The referral is to a note in "Inside the Third Reich" which itself refers to Speer's Office diary citing his office journal in March 1944.
Going from this, another deep session of internet search gave out a forum post with the following content:

""A document was from the German Army Ordnance Command (Heeresamt/Heereswaffenamt) about a experimental-commando (Versuchskommando 515) with a staff and two experimental-companies.

1. Company with 2 Tigers, 2 Kingtigers and 5 Panthers are used the uranium-cored ammunition and tested it against Soviet tanks near the town of Posen in Poland.

2. Company with guided anti-tank missiles called "Rotk├Ąppchen" on Halftracks also fighted against Soviet breakthrough┬┤s near Posen.
There was some infantry to accompany.

In the document the uran-ammunition and the missiles performed very well and the leader of the Experimental-commando says in his statement that the ammunition was many times better than the tungsten-cored round PzGr.40.

Sadly I couldn't find the document but it must be accessible to the public in german archives.
Unfortunately as I'm not german (and sadly don't speak it either) this is the limit of my research.

We do know that uranium ammo testing is definitely real and the forum post above (plus some others claiming an uranium 5cm round was found in Belgium) might very well be based on a real document but proving this will need someone to do the final part of the digging.

With this I'm asking to anyone in germany that could potentially spend some times in the old archives if they are interested to try to dig the document and get a pic or a scan of it.
If successfull, this could unlock knowledge of one of the last "secret weapons" of WWII and potentially a way to ask WG to buff certain german guns.

I cannot offer any reward to this aside from my personal gratitude but whoever will succeed can be proud of having solved one of the last historical mysteries of WWII weaponry.

More pointers:

- Does anyone have "Truth about the Wunderwaffe" by Igor Witkowski?
I found a mention that on page 117 an area near Mieleck is still contaminated by Uranium from WW2 trials with Uranium core amunition.

- Apparently there is a document from 04.03.1945 about the use of uranium-cored
armor piercing rounds in the German Army history center in Koblenz

- There are also mentions of a pre-WWII Rheinmetall patent on the use of uranium cores.