What caliber? Or hmm what is it?

[AGBlex]

About the size of a penny. Has interesting notched ring around it. Maybe it's not a bullet!

 

Amazon Forum Fav 👍

DR.ÖTEK Metal Detector, Waterproof Gold Detector, Pinpoint & Terrain Modes, Professional Metal Detector - Grab it through Amazon!

[releventchair]

It is the jacket to a bullet.
Your interesting notched ring around it is a cannelure. It helps prevent bullet set back.
The lead core of the bullet is gone.
There are visible rifling marks from the barrel it was fired from that show as well.
You'd need to measure the base to estimate caliber. It may have expanded a little.

 

[Tony in SC]

It is a modern bullet. Get a diameter on the base. It;s the only part that is still round.

 

[AGBlex]

Huh! Wicked interesting. It is 8mm, the round part

 

[Radon]

That's pretty close to a .32 caliber pistol round.

 

[Charlie P. (NY)]

The base is typical of a full-metal jacket bullet (frequently surplus ammo). 8mm was the German rifle bore of WWI and WWII. Many countries used bores close to that. LOTS of surplus rifles came into the US (still do).

 

[AGBlex]

The base is typical of a full-metal jacket bullet (frequently surplus ammo). 8mm was the German rifle bore of WWI and WWII. Many countries used bores close to that. LOTS of surplus rifles came into the US (still do).

Awesome! Thank you for the info!

 

[A2coins]

Right on the money though it did shape kinda funny