New to coins and found this 1966 quarter with what looks like a ring around the outside. The ring goes all the way around at a consistent distance from the edge. Unsure if it’s caused by damage or was a mint error.
Over vigorous crimping ... here is an example of a manual crimper .. go to the 4 minute mark (62) Klopp International coin roll crimping machine! - YouTube
Welcome to Coin Talk. As stated, it is damage from being the last coin in a roll and the machine that seals the end will often damage the coin. Good hunting.
