That's the 50 caliber sabot I mentioned. It is the only one of its kind. I have yet to read a single report of success. It is a poor design that does not shoot accurately for various reasons. If you ever compare them to a sabot from a factory round, it makes sense. The RSS is relatively soft, and the huge gaps between the petals doesn't add support. Also the base is thin, and prone to having the bullet break through the bottom. Compare that to something like a sabot from a SST, and they are harder, and fully supported. There have been variations of the SST load, but they usually have an aluminum and or rubber disk for support in the base. I've got some sabots from a Federal trophy copper, and those sabots are built with incredibly hard plastic, almost like UHMW, and have a thick aluminum washer for the base.