I posted a mysterious ww2 bullet yesterday looking for some ID on it, and I think i found out what it is.
Going through some of my older finds from that area, I have similar bullets, which are .50 cal with the jacket partially or entirely missing.
Picture 1 shows the original bullet next to a .50 with the damaged jacket coming off the core.
Picture 2 shows a intact .50 cal next to a .50 with an damaged jacket, next to the original bullet.
Picture 3 shows the original bullet next to the core of a .50 taken out of the damaged jacket, with the extracted jacket next to it.