Can ya post pic of top and bottom....just wondered if solid or hollow as well as threaded. Most lead gets a white patina. It looks too long for a bullet plus it appears to have a seam in the middle.
I think you might have a Nichols '45, 2-piece bullet (for a toy cap pistol) that
was popular back in the late 1950's. A round Stallion cap was placed in a
shortened bullet shell and the part you found was placed in the shell.