I think people hesitated to identify this bullet because they didn't know what to make of it, but since Pistol Pete took the bull by the horns I will add my two cents worth. As Pistol Pete observed, it is just the right shape and size to be a .38 pistol bullet for use in a .38 special, .38 long Colt and perhaps .38 S&W revolver. It could also conceivably have been made for use in a 9mm or .38 acp pistol. The thing about it that I don't understand is why the point should be copper and the base lead. If it were a half jacket or a lead bullet fitted with a gas check it would be just the opposite. The only thing that suggests itself to my mind is that it is a copper-plated bullet of the type sold for reloading that has lost the plating at the base, perhaps during the reloading process, but retained it towards the point. If this is the case, scratching the copper point with a sharp implement would remove the thin plating and allow the lead to show through. As Pistol Pete said, and as you yourself suspect, it is most likely rather recent.