How old is this bullet

[RelicDude]

Today I detected a farm field and dug up this three ring I'm just curious of how old it is. Thank you in advance - Justin

 

[BosnMate]

Need measurements in 1/1000's of an inch. cartridge bullets are a few 1/1000's over bore size of the gun. For example, I shoot a .45 caliber rifle, but the bullet I shoot in that gun is .457.

 

[TheCannonballGuy]

Both of your photos are out-of-focus, so I can't be sure on the ID, but it resembles a (fired) .52 Spencer Rifle bullet. That rifle was in use from the civil war through several decades afterward. To dtermine your bullet's time-period, we need to know whether it not it has "reeding" in the body-grooves, as shown in the photo below. If its grooves are "reeded, it dates from no earlier than the late-1870s.