How do can you tell whether a bullet is plated or jacketed?

scratch it is the easiest if you don't recognize plating.. the plating is very thin and a little nick with a jackknife you will see the lead core

all of the plated bullets i have seen are smoothly plated all around the bullet and bas. there shouldnt be any visible lines or lead. where most of the jacketd bullets i have seen have either exposed lead at the bottom or a seperation in the jacket at the bottom.