Hi there,
I can tell from your bullet, that it is an "outside" lubricated type .That cannelure or groove with the serrations held the lubricant, which was probably a beeswax and tallow mix.
The smooth portion below it would have been crimped into the brass or copper shell to hold it in place. This is pretty much how modern day .22 bullets are designed.
But since yours is much larger, I'm thinking .38 or possibly .44 , it could have came from any one of a dozen or so different different cartridges popular from the 1870's to the early 20th century.
I.E. .38 short, long, or extra long . Ditto for .44.