50 Cal/20mm HV Experimental

What is the correct name for this cartridge? I think I saw a FMJ projectile in a similar case called a Uniroyal experimental. I can find no links for Uniroyal making ammo since Eau Claire in WW2. What year was this item made? (1980’s?)
It looks like a 20mm M103 necked to 12.7mm then a .30 AP black tip projectile in a clear sabot. No headstamp. Electric primed. 32mm Projectile length as shown above mouth.
Any info on weapon type, use or history will be appreciated.


You can find this cartridge in the ECRA Data Viewer with the number 13 101 BGE 010.
The name of this cartridge is “20mm/.50 US XPL Lake City for Helicopter fuel cell test” and the production is ca. 1970.

rigby, does the ECRA viewer show this specific loading of that cartridge?

The sabot looks to be the same as that used in the Teppo Jutsu .500 Phantom cartridge shown below, from my web article on these rounds: http://quarryhs.co.uk/TeppoJutsu.htm

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No sorry.

The sabot/projectile in the uniroyal case is not correct to the case. The correct bullet was ball or ap .50. The sabot was for people to shoot .30 bullets in a standard .50 case and .22 bullets in a .30 case. (2 different sabot models, clear or blue plastic sabots) It was intended for individual hand loaders, in the USA, not a factory design. Even the sabot producers could not provide load data and openly asked for anyone that successfully loaded them, to notify them of the load they used. It was not a popular or widely used design, but was advertised for sale.