Welcome to the Treasurenet forum allsilentearth! Your photo is helpful because of your digits holding the bullet provide a size reference of sorts. That's a big bullet,and likely of Civil war vintage. A photo of the bullet's base would be helpful,as it should have a hollow or deeply indented base. Those three ring bullets come in .54",.58",and maybe .68" diameter. From your photo,it appears to be a dropped (unfired) bullet. The Civil War Relicman is a dealer in relics who has a very informative website. His photos will show you examples of bullet types and other relics you might find. Take a look at his website for a quick basic education.