Nice. If you would in the future post these type items over at the Weapons & Ammo forum we can take a look and get a lot better response. Plus if you could post a photo of the base it would be helpful.
I agree that better pictures of the base should be posted. From the pictures shown, it looks as if it could be a modern fishing weight as much as any pistol bullet.
ok here us a pics of side,bottom and top there is no hole through it and I have found several pistol bullets in the vicinity of this one but this is the only one like this. This field has been a gold mind for dropped bullets 69s 58s and 54 calibers plus pistol bullets.