Can someone identify this bullet for mr?

[jcp1960]

I found this today in the same area where I recently found a USC Co. 1918 bullet. As you can see from the picture it has two rings and a third thinner ring on top. Any info would be greatly appreciated.

 

[jewelerguy]

it's a relatively modern bullet. measurements would help identify the caliber

 

[Charlie P. (NY)]

Dimensions in thousandths? Hollow base or solid? Weight in grains would be keen as well.