Reed Marks From Another Coin
So we probably average about one damaged coin like this a week on the forum. They are damaged by other coins in the ballistic bag.
The coins are damaged when the ballistic bags are moved around by forklifts. They way thousands of pounds. We most commonly see them on quarters, but can happen on any coins with reeding.
Here are some samples plus a picture of a ballistic bag of quarters. Click images to enlarge.