What kind of bullet is this?

[Digging Fool]

Hello, Pappy. I have been meaning to submit this for quite some time now, but kept forgetting. I found this "unusual" bullet that is VERY hollow in the base, with kinda thin sidewalls. Never found one this "hollowed out". It looks to have been made that way, and shows rifle grooves where it was shot. I have never found another like it, and have found around a thousand bullets. Thanks!

[superduty]

Looks like a mini ball. The base was made like that so it would expland to help seat it into the rifling of the gun barrel . Some round was made to do that I think they where called miniballs ?? A Soldier's Gun

[PAPPY]

Minié ball - Wikipedia, the free encyclopedia

[Digging Fool]

I would have thought that, out of ALL those other bullets, I would have found another like this one, but for some reason, this one looks different. Perhaps where I hunt there weren't many of this type used?? Anyway, Thanks for the response!

[Tn Dirt Digger]

That bullet is in good shape...will look pretty cool in your display case!